lib/tevent: close pipe_fds on event_context destruction
[ira/wip.git] / lib / tevent / tevent.c
index 4c87ef5f733ad24a686715bbfdf3d78a760157bf..56d0da39276ee3489b59b8d81ab495d601266903 100644 (file)
@@ -2,19 +2,24 @@
    Unix SMB/CIFS implementation.
    main select loop and event handling
    Copyright (C) Andrew Tridgell 2003
-   
-   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,
+   Copyright (C) Stefan Metzmacher 2009
+
+     ** 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 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/>.
+   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/>.
 */
 
 /*
      handler to get another event.
 
   To setup a set of events you first need to create a event_context
-  structure using the function event_context_init(); This returns a
+  structure using the function tevent_context_init(); This returns a
   'struct tevent_context' that you use in all subsequent calls.
 
   After that you can add/remove events that you are interested in
-  using event_add_*() and talloc_free()
+  using tevent_add_*() and talloc_free()
 
   Finally, you call tevent_loop_wait_once() to block waiting for one of the
   events to occor or tevent_loop_wait() which will loop
 
 */
 #include "replace.h"
+#include "system/filesys.h"
+#define TEVENT_DEPRECATED 1
 #include "tevent.h"
 #include "tevent_internal.h"
 #include "tevent_util.h"
 
-struct event_ops_list {
-       struct event_ops_list *next, *prev;
+struct tevent_ops_list {
+       struct tevent_ops_list *next, *prev;
        const char *name;
-       const struct event_ops *ops;
+       const struct tevent_ops *ops;
 };
 
 /* list of registered event backends */
-static struct event_ops_list *event_backends = NULL;
+static struct tevent_ops_list *tevent_backends = NULL;
 static char *tevent_default_backend = NULL;
 
 /*
   register an events backend
 */
-bool event_register_backend(const char *name, const struct event_ops *ops)
+bool tevent_register_backend(const char *name, const struct tevent_ops *ops)
 {
-       struct event_ops_list *e;
+       struct tevent_ops_list *e;
 
-       for (e = event_backends; e != NULL; e = e->next) {
+       for (e = tevent_backends; e != NULL; e = e->next) {
                if (0 == strcmp(e->name, name)) {
                        /* already registered, skip it */
                        return true;
                }
        }
 
-       e = talloc(talloc_autofree_context(), struct event_ops_list);
+       e = talloc(talloc_autofree_context(), struct tevent_ops_list);
        if (e == NULL) return false;
 
        e->name = name;
        e->ops = ops;
-       DLIST_ADD(event_backends, e);
+       DLIST_ADD(tevent_backends, e);
 
        return true;
 }
@@ -104,29 +111,26 @@ void tevent_set_default_backend(const char *backend)
 /*
   initialise backends if not already done
 */
-static void event_backend_init(void)
+static void tevent_backend_init(void)
 {
-       events_select_init();
-       events_standard_init();
-#if HAVE_EVENTS_EPOLL
-       events_epoll_init();
-#endif
-#if HAVE_LINUX_AIO
-       events_aio_init();
+       tevent_select_init();
+       tevent_standard_init();
+#ifdef HAVE_EPOLL
+       tevent_epoll_init();
 #endif
 }
 
 /*
   list available backends
 */
-const char **event_backend_list(TALLOC_CTX *mem_ctx)
+const char **tevent_backend_list(TALLOC_CTX *mem_ctx)
 {
        const char **list = NULL;
-       struct event_ops_list *e;
+       struct tevent_ops_list *e;
 
-       event_backend_init();
+       tevent_backend_init();
 
-       for (e=event_backends;e;e=e->next) {
+       for (e=tevent_backends;e;e=e->next) {
                list = ev_str_list_add(list, e->name);
        }
 
@@ -135,6 +139,48 @@ const char **event_backend_list(TALLOC_CTX *mem_ctx)
        return list;
 }
 
+int tevent_common_context_destructor(struct tevent_context *ev)
+{
+       struct tevent_fd *fd, *fn;
+       struct tevent_timer *te, *tn;
+       struct tevent_immediate *ie, *in;
+       struct tevent_signal *se, *sn;
+
+       if (ev->pipe_fde) {
+               talloc_free(ev->pipe_fde);
+               close(ev->pipe_fds[0]);
+               close(ev->pipe_fds[1]);
+               ev->pipe_fde = NULL;
+       }
+
+       for (fd = ev->fd_events; fd; fd = fn) {
+               fn = fd->next;
+               fd->event_ctx = NULL;
+               DLIST_REMOVE(ev->fd_events, fd);
+       }
+
+       for (te = ev->timer_events; te; te = tn) {
+               tn = te->next;
+               te->event_ctx = NULL;
+               DLIST_REMOVE(ev->timer_events, te);
+       }
+
+       for (ie = ev->immediate_events; ie; ie = in) {
+               in = ie->next;
+               ie->event_ctx = NULL;
+               ie->cancel_fn = NULL;
+               DLIST_REMOVE(ev->immediate_events, ie);
+       }
+
+       for (se = ev->signal_events; se; se = sn) {
+               sn = se->next;
+               se->event_ctx = NULL;
+               DLIST_REMOVE(ev->signal_events, se);
+       }
+
+       return 0;
+}
+
 /*
   create a event_context structure for a specific implemementation.
   This must be the first events call, and all subsequent calls pass
@@ -144,10 +190,10 @@ const char **event_backend_list(TALLOC_CTX *mem_ctx)
   This function is for allowing third-party-applications to hook in gluecode
   to their own event loop code, so that they can make async usage of our client libs
 
-  NOTE: use event_context_init() inside of samba!
+  NOTE: use tevent_context_init() inside of samba!
 */
-static struct tevent_context *event_context_init_ops(TALLOC_CTX *mem_ctx, 
-                                                   const struct event_ops *ops)
+static struct tevent_context *tevent_context_init_ops(TALLOC_CTX *mem_ctx,
+                                                     const struct tevent_ops *ops)
 {
        struct tevent_context *ev;
        int ret;
@@ -155,6 +201,8 @@ static struct tevent_context *event_context_init_ops(TALLOC_CTX *mem_ctx,
        ev = talloc_zero(mem_ctx, struct tevent_context);
        if (!ev) return NULL;
 
+       talloc_set_destructor(ev, tevent_common_context_destructor);
+
        ev->ops = ops;
 
        ret = ev->ops->context_init(ev);
@@ -171,11 +219,12 @@ static struct tevent_context *event_context_init_ops(TALLOC_CTX *mem_ctx,
   call, and all subsequent calls pass this event_context as the first
   element. Event handlers also receive this as their first argument.
 */
-struct tevent_context *event_context_init_byname(TALLOC_CTX *mem_ctx, const char *name)
+struct tevent_context *tevent_context_init_byname(TALLOC_CTX *mem_ctx,
+                                                 const char *name)
 {
-       struct event_ops_list *e;
+       struct tevent_ops_list *e;
 
-       event_backend_init();
+       tevent_backend_init();
 
        if (name == NULL) {
                name = tevent_default_backend;
@@ -184,9 +233,9 @@ struct tevent_context *event_context_init_byname(TALLOC_CTX *mem_ctx, const char
                name = "standard";
        }
 
-       for (e=event_backends;e;e=e->next) {
+       for (e=tevent_backends;e;e=e->next) {
                if (strcmp(name, e->name) == 0) {
-                       return event_context_init_ops(mem_ctx, e->ops);
+                       return tevent_context_init_ops(mem_ctx, e->ops);
                }
        }
        return NULL;
@@ -198,36 +247,53 @@ struct tevent_context *event_context_init_byname(TALLOC_CTX *mem_ctx, const char
   call, and all subsequent calls pass this event_context as the first
   element. Event handlers also receive this as their first argument.
 */
-struct tevent_context *event_context_init(TALLOC_CTX *mem_ctx)
+struct tevent_context *tevent_context_init(TALLOC_CTX *mem_ctx)
 {
-       return event_context_init_byname(mem_ctx, NULL);
+       return tevent_context_init_byname(mem_ctx, NULL);
 }
 
 /*
   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
+  if flags contains TEVENT_FD_AUTOCLOSE then the fd will be closed when
   the returned fd_event context is freed
 */
-struct tevent_fd *event_add_fd(struct tevent_context *ev, TALLOC_CTX *mem_ctx,
-                             int fd, uint16_t flags, event_fd_handler_t handler,
-                             void *private_data)
+struct tevent_fd *_tevent_add_fd(struct tevent_context *ev,
+                                TALLOC_CTX *mem_ctx,
+                                int fd,
+                                uint16_t flags,
+                                tevent_fd_handler_t handler,
+                                void *private_data,
+                                const char *handler_name,
+                                const char *location)
 {
-       return ev->ops->add_fd(ev, mem_ctx, fd, flags, handler, private_data);
+       return ev->ops->add_fd(ev, mem_ctx, fd, flags, handler, private_data,
+                              handler_name, location);
 }
 
 /*
-  add a disk aio event
+  set a close function on the fd event
 */
-struct aio_event *event_add_aio(struct tevent_context *ev,
-                               TALLOC_CTX *mem_ctx,
-                               struct iocb *iocb,
-                               event_aio_handler_t handler,
-                               void *private_data)
+void tevent_fd_set_close_fn(struct tevent_fd *fde,
+                           tevent_fd_close_fn_t close_fn)
+{
+       if (!fde) return;
+       if (!fde->event_ctx) return;
+       fde->event_ctx->ops->set_fd_close_fn(fde, close_fn);
+}
+
+static void tevent_fd_auto_close_fn(struct tevent_context *ev,
+                                   struct tevent_fd *fde,
+                                   int fd,
+                                   void *private_data)
+{
+       close(fd);
+}
+
+void tevent_fd_set_auto_close(struct tevent_fd *fde)
 {
-       if (ev->ops->add_aio == NULL) return NULL;
-       return ev->ops->add_aio(ev, mem_ctx, iocb, handler, private_data);
+       tevent_fd_set_close_fn(fde, tevent_fd_auto_close_fn);
 }
 
 /*
@@ -236,6 +302,7 @@ struct aio_event *event_add_aio(struct tevent_context *ev,
 uint16_t tevent_fd_get_flags(struct tevent_fd *fde)
 {
        if (!fde) return 0;
+       if (!fde->event_ctx) return 0;
        return fde->event_ctx->ops->get_fd_flags(fde);
 }
 
@@ -245,19 +312,92 @@ uint16_t tevent_fd_get_flags(struct tevent_fd *fde)
 void tevent_fd_set_flags(struct tevent_fd *fde, uint16_t flags)
 {
        if (!fde) return;
+       if (!fde->event_ctx) return;
        fde->event_ctx->ops->set_fd_flags(fde, flags);
 }
 
+bool tevent_signal_support(struct tevent_context *ev)
+{
+       if (ev->ops->add_signal) {
+               return true;
+       }
+       return false;
+}
+
+static void (*tevent_abort_fn)(const char *reason);
+
+void tevent_set_abort_fn(void (*abort_fn)(const char *reason))
+{
+       tevent_abort_fn = abort_fn;
+}
+
+static void tevent_abort(struct tevent_context *ev, const char *reason)
+{
+       tevent_debug(ev, TEVENT_DEBUG_FATAL,
+                    "abort: %s\n", reason);
+
+       if (!tevent_abort_fn) {
+               abort();
+       }
+
+       tevent_abort_fn(reason);
+}
+
 /*
-  add a timed event
+  add a timer event
   return NULL on failure
 */
-struct tevent_timer *event_add_timed(struct tevent_context *ev, TALLOC_CTX *mem_ctx,
-                                   struct timeval next_event, 
-                                   event_timed_handler_t handler, 
-                                   void *private_data)
+struct tevent_timer *_tevent_add_timer(struct tevent_context *ev,
+                                      TALLOC_CTX *mem_ctx,
+                                      struct timeval next_event,
+                                      tevent_timer_handler_t handler,
+                                      void *private_data,
+                                      const char *handler_name,
+                                      const char *location)
 {
-       return ev->ops->add_timer(ev, mem_ctx, next_event, handler, private_data);
+       return ev->ops->add_timer(ev, mem_ctx, next_event, handler, private_data,
+                                 handler_name, location);
+}
+
+/*
+  allocate an immediate event
+  return NULL on failure (memory allocation error)
+*/
+struct tevent_immediate *_tevent_create_immediate(TALLOC_CTX *mem_ctx,
+                                                 const char *location)
+{
+       struct tevent_immediate *im;
+
+       im = talloc(mem_ctx, struct tevent_immediate);
+       if (im == NULL) return NULL;
+
+       im->prev                = NULL;
+       im->next                = NULL;
+       im->event_ctx           = NULL;
+       im->create_location     = location;
+       im->handler             = NULL;
+       im->private_data        = NULL;
+       im->handler_name        = NULL;
+       im->schedule_location   = NULL;
+       im->cancel_fn           = NULL;
+       im->additional_data     = NULL;
+
+       return im;
+}
+
+/*
+  schedule an immediate event
+  return NULL on failure
+*/
+void _tevent_schedule_immediate(struct tevent_immediate *im,
+                               struct tevent_context *ev,
+                               tevent_immediate_handler_t handler,
+                               void *private_data,
+                               const char *handler_name,
+                               const char *location)
+{
+       ev->ops->schedule_immediate(im, ev, handler, private_data,
+                                   handler_name, location);
 }
 
 /*
@@ -267,27 +407,205 @@ struct tevent_timer *event_add_timed(struct tevent_context *ev, TALLOC_CTX *mem_
 
   return NULL on failure
 */
-struct signal_event *event_add_signal(struct tevent_context *ev, TALLOC_CTX *mem_ctx,
-                                     int signum,
-                                     int sa_flags,
-                                     event_signal_handler_t handler, 
-                                     void *private_data)
+struct tevent_signal *_tevent_add_signal(struct tevent_context *ev,
+                                        TALLOC_CTX *mem_ctx,
+                                        int signum,
+                                        int sa_flags,
+                                        tevent_signal_handler_t handler,
+                                        void *private_data,
+                                        const char *handler_name,
+                                        const char *location)
+{
+       return ev->ops->add_signal(ev, mem_ctx, signum, sa_flags, handler, private_data,
+                                  handler_name, location);
+}
+
+void tevent_loop_allow_nesting(struct tevent_context *ev)
+{
+       ev->nesting.allowed = true;
+}
+
+void tevent_loop_set_nesting_hook(struct tevent_context *ev,
+                                 tevent_nesting_hook hook,
+                                 void *private_data)
 {
-       return ev->ops->add_signal(ev, mem_ctx, signum, sa_flags, handler, private_data);
+       if (ev->nesting.hook_fn && 
+           (ev->nesting.hook_fn != hook ||
+            ev->nesting.hook_private != private_data)) {
+               /* the way the nesting hook code is currently written
+                  we cannot support two different nesting hooks at the
+                  same time. */
+               tevent_abort(ev, "tevent: Violation of nesting hook rules\n");
+       }
+       ev->nesting.hook_fn = hook;
+       ev->nesting.hook_private = private_data;
+}
+
+static void tevent_abort_nesting(struct tevent_context *ev, const char *location)
+{
+       const char *reason;
+
+       reason = talloc_asprintf(NULL, "tevent_loop_once() nesting at %s",
+                                location);
+       if (!reason) {
+               reason = "tevent_loop_once() nesting";
+       }
+
+       tevent_abort(ev, reason);
 }
 
 /*
   do a single event loop using the events defined in ev 
 */
-int tevent_loop_once(struct tevent_context *ev)
+int _tevent_loop_once(struct tevent_context *ev, const char *location)
+{
+       int ret;
+       void *nesting_stack_ptr = NULL;
+
+       ev->nesting.level++;
+
+       if (ev->nesting.level > 1) {
+               if (!ev->nesting.allowed) {
+                       tevent_abort_nesting(ev, location);
+                       errno = ELOOP;
+                       return -1;
+               }
+       }
+       if (ev->nesting.level > 0) {
+               if (ev->nesting.hook_fn) {
+                       int ret2;
+                       ret2 = ev->nesting.hook_fn(ev,
+                                                  ev->nesting.hook_private,
+                                                  ev->nesting.level,
+                                                  true,
+                                                  (void *)&nesting_stack_ptr,
+                                                  location);
+                       if (ret2 != 0) {
+                               ret = ret2;
+                               goto done;
+                       }
+               }
+       }
+
+       ret = ev->ops->loop_once(ev, location);
+
+       if (ev->nesting.level > 0) {
+               if (ev->nesting.hook_fn) {
+                       int ret2;
+                       ret2 = ev->nesting.hook_fn(ev,
+                                                  ev->nesting.hook_private,
+                                                  ev->nesting.level,
+                                                  false,
+                                                  (void *)&nesting_stack_ptr,
+                                                  location);
+                       if (ret2 != 0) {
+                               ret = ret2;
+                               goto done;
+                       }
+               }
+       }
+
+done:
+       ev->nesting.level--;
+       return ret;
+}
+
+/*
+  this is a performance optimization for the samba4 nested event loop problems
+*/
+int _tevent_loop_until(struct tevent_context *ev,
+                      bool (*finished)(void *private_data),
+                      void *private_data,
+                      const char *location)
+{
+       int ret = 0;
+       void *nesting_stack_ptr = NULL;
+
+       ev->nesting.level++;
+
+       if (ev->nesting.level > 1) {
+               if (!ev->nesting.allowed) {
+                       tevent_abort_nesting(ev, location);
+                       errno = ELOOP;
+                       return -1;
+               }
+       }
+       if (ev->nesting.level > 0) {
+               if (ev->nesting.hook_fn) {
+                       int ret2;
+                       ret2 = ev->nesting.hook_fn(ev,
+                                                  ev->nesting.hook_private,
+                                                  ev->nesting.level,
+                                                  true,
+                                                  (void *)&nesting_stack_ptr,
+                                                  location);
+                       if (ret2 != 0) {
+                               ret = ret2;
+                               goto done;
+                       }
+               }
+       }
+
+       while (!finished(private_data)) {
+               ret = ev->ops->loop_once(ev, location);
+               if (ret != 0) {
+                       break;
+               }
+       }
+
+       if (ev->nesting.level > 0) {
+               if (ev->nesting.hook_fn) {
+                       int ret2;
+                       ret2 = ev->nesting.hook_fn(ev,
+                                                  ev->nesting.hook_private,
+                                                  ev->nesting.level,
+                                                  false,
+                                                  (void *)&nesting_stack_ptr,
+                                                  location);
+                       if (ret2 != 0) {
+                               ret = ret2;
+                               goto done;
+                       }
+               }
+       }
+
+done:
+       ev->nesting.level--;
+       return ret;
+}
+
+/*
+  return on failure or (with 0) if all fd events are removed
+*/
+int tevent_common_loop_wait(struct tevent_context *ev,
+                           const char *location)
 {
-       return ev->ops->loop_once(ev);
+       /*
+        * loop as long as we have events pending
+        */
+       while (ev->fd_events ||
+              ev->timer_events ||
+              ev->immediate_events ||
+              ev->signal_events) {
+               int ret;
+               ret = _tevent_loop_once(ev, location);
+               if (ret != 0) {
+                       tevent_debug(ev, TEVENT_DEBUG_FATAL,
+                                    "_tevent_loop_once() failed: %d - %s\n",
+                                    ret, strerror(errno));
+                       return ret;
+               }
+       }
+
+       tevent_debug(ev, TEVENT_DEBUG_WARNING,
+                    "tevent_common_loop_wait() out of events\n");
+       return 0;
 }
 
 /*
   return on failure or (with 0) if all fd events are removed
 */
-int tevent_loop_wait(struct tevent_context *ev)
+int _tevent_loop_wait(struct tevent_context *ev, const char *location)
 {
-       return ev->ops->loop_wait(ev);
+       return ev->ops->loop_wait(ev, location);
 }