r20928: added signal events to lib/events
authorAndrew Tridgell <tridge@samba.org>
Sun, 21 Jan 2007 08:23:14 +0000 (08:23 +0000)
committerGerald (Jerry) Carter <jerry@samba.org>
Wed, 10 Oct 2007 19:43:54 +0000 (14:43 -0500)
Jeremy asked for this to allow Samba3 to use the Samba4 events library

see torture/local/event.c for an example
(This used to be commit 7e105482ff9a3da6b4708ff99a64f1881614fc5f)

source4/lib/events/config.mk
source4/lib/events/events.c
source4/lib/events/events.h
source4/lib/events/events_aio.c
source4/lib/events/events_epoll.c
source4/lib/events/events_internal.h
source4/lib/events/events_liboop.c
source4/lib/events/events_select.c
source4/lib/events/events_signal.c [new file with mode: 0644]
source4/lib/events/events_standard.c

index 5830ca38f42e590846c4b3c687e5e6416d8eecf2..0a1a3bf0f99e7f078a299f3e9625234fc68ae457 100644 (file)
@@ -31,7 +31,7 @@ INIT_FUNCTION = events_standard_init
 ##############################
 # Start SUBSYSTEM LIBEVENTS
 [SUBSYSTEM::LIBEVENTS]
-OBJ_FILES = events.o events_timed.o
+OBJ_FILES = events.o events_timed.o events_signal.o
 PUBLIC_DEPENDENCIES = LIBTALLOC
 # End SUBSYSTEM LIBEVENTS
 ##############################
index 6159ea147f152417dcece058ebb7d7c2c766971c..38f2352f3b0e1f96634399b234690a740430259c 100644 (file)
@@ -239,6 +239,18 @@ struct timed_event *event_add_timed(struct event_context *ev, TALLOC_CTX *mem_ct
        return ev->ops->add_timed(ev, mem_ctx, next_event, handler, private_data);
 }
 
+/*
+  add a signal event
+  return NULL on failure
+*/
+struct timed_event *event_add_signal(struct event_context *ev, TALLOC_CTX *mem_ctx,
+                                    int signum,
+                                    event_signal_handler_t handler, 
+                                    void *private_data)
+{
+       return ev->ops->add_signal(ev, mem_ctx, signum, handler, private_data);
+}
+
 /*
   do a single event loop using the events defined in ev 
 */
index 62f1d8e9df5dbd0c855bd96983fabcf63438e20b..eee7a5e47048f2e14765faeaadbaf13646e5c615 100644 (file)
@@ -28,14 +28,17 @@ struct event_ops;
 struct fd_event;
 struct timed_event;
 struct aio_event;
+struct signal_event;
 
 /* event handler types */
 typedef void (*event_fd_handler_t)(struct event_context *, struct fd_event *, 
                                   uint16_t , void *);
 typedef void (*event_timed_handler_t)(struct event_context *, struct timed_event *, 
                                      struct timeval , void *);
+typedef void (*event_signal_handler_t)(struct event_context *, struct signal_event *, 
+                                      int , int, void *);
 typedef void (*event_aio_handler_t)(struct event_context *, struct aio_event *, 
-                                   int , void *);
+                                   int, void *);
 
 struct event_context *event_context_init(TALLOC_CTX *mem_ctx);
 struct event_context *event_context_init_byname(TALLOC_CTX *mem_ctx, const char *name);
@@ -50,6 +53,11 @@ struct timed_event *event_add_timed(struct event_context *ev, TALLOC_CTX *mem_ct
                                    event_timed_handler_t handler, 
                                    void *private);
 
+struct signal_event *event_add_signal(struct event_context *ev, TALLOC_CTX *mem_ctx,
+                                     int signum,
+                                     event_signal_handler_t handler, 
+                                     void *private);
+
 struct iocb;
 struct aio_event *event_add_aio(struct event_context *ev,
                                TALLOC_CTX *mem_ctx,
index 6d9dd6d7538913dcb0d42e6760a71ebeff6415ab..327b36bcba12424d65c6ee34e00de3d0059dd302 100644 (file)
@@ -225,6 +225,11 @@ static int aio_event_loop(struct aio_event_context *aio_ev, struct timeval *tval
 
        if (aio_ev->epoll_fd == -1) return -1;
 
+       if (aio_ev->ev->num_signal_handlers && 
+           common_event_check_signal(aio_ev->ev)) {
+               return 0;
+       }
+
        if (tvalp) {
                timeout.tv_sec = tvalp->tv_sec;
                timeout.tv_nsec = tvalp->tv_usec;
@@ -236,7 +241,11 @@ static int aio_event_loop(struct aio_event_context *aio_ev, struct timeval *tval
 
        ret = io_getevents(aio_ev->ioctx, 1, 8,
                           events, tvalp?&timeout:NULL);
+
        if (ret == -EINTR) {
+               if (aio_ev->ev->num_signal_handlers) {
+                       common_event_check_signal(aio_ev->ev);
+               }
                return 0;
        }
 
@@ -488,6 +497,7 @@ static const struct event_ops aio_event_ops = {
        .get_fd_flags   = aio_event_get_fd_flags,
        .set_fd_flags   = aio_event_set_fd_flags,
        .add_timed      = common_event_add_timed,
+       .add_signal     = common_event_add_signal,
        .loop_once      = aio_event_loop_once,
        .loop_wait      = aio_event_loop_wait,
 };
index f69b5bc6f49a6af0b3249a289322945ceafd9bd5..efcbb97f0b3978df2cd7cebf4b10f50145d8956a 100644 (file)
@@ -214,8 +214,19 @@ static int epoll_event_loop(struct epoll_event_context *epoll_ev, struct timeval
                timeout = ((tvalp->tv_usec+999) / 1000) + (tvalp->tv_sec*1000);
        }
 
+       if (epoll_ev->ev->num_signal_handlers && 
+           common_event_check_signal(epoll_ev->ev)) {
+               return 0;
+       }
+
        ret = epoll_wait(epoll_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)) {
+                       return 0;
+               }
+       }
+
        if (ret == -1 && errno != EINTR) {
                epoll_fallback_to_select(epoll_ev, "epoll_wait() failed");
                return -1;
@@ -397,6 +408,7 @@ static const struct event_ops epoll_event_ops = {
        .get_fd_flags   = epoll_event_get_fd_flags,
        .set_fd_flags   = epoll_event_set_fd_flags,
        .add_timed      = common_event_add_timed,
+       .add_signal     = common_event_add_signal,
        .loop_once      = epoll_event_loop_once,
        .loop_wait      = epoll_event_loop_wait,
 };
index dc321769e0af097e1e85cae5c906710c371a3d32..0b8de12a3540196a1e52fc1b850b828126dcb023 100644 (file)
@@ -47,6 +47,12 @@ struct event_ops {
                                     struct iocb *iocb, 
                                     event_aio_handler_t handler, 
                                     void *private_data);
+       /* signal functions */
+       struct signal_event *(*add_signal)(struct event_context *ev, 
+                                          TALLOC_CTX *mem_ctx,
+                                          int signum,
+                                          event_signal_handler_t handler, 
+                                          void *private_data);
 
        /* loop functions */
        int (*loop_once)(struct event_context *ev);
@@ -77,6 +83,14 @@ struct timed_event {
        void *additional_data;
 };
 
+struct signal_event {
+       struct signal_event *prev, *next;
+       struct event_context *event_ctx;
+       event_signal_handler_t handler;
+       void *private_data;
+       int signum;
+};
+
 /* aio event is private to the aio backend */
 struct aio_event;
 
@@ -89,6 +103,12 @@ struct event_context {
 
        /* this is private for the events_ops implementation */
        void *additional_data;
+
+       /* number of signal event handlers */
+       int num_signal_handlers;
+
+       /* pipe hack used with signal handlers */
+       struct fd_event *pipe_fde;
 };
 
 
@@ -98,3 +118,11 @@ struct timed_event *common_event_add_timed(struct event_context *, TALLOC_CTX *,
                                           struct timeval, event_timed_handler_t, void *);
 void common_event_loop_timer(struct event_context *);
 struct timeval common_event_loop_delay(struct event_context *);
+
+struct signal_event *common_event_add_signal(struct event_context *ev, 
+                                            TALLOC_CTX *mem_ctx,
+                                            int signum,
+                                            event_signal_handler_t handler, 
+                                            void *private_data);
+int common_event_check_signal(struct event_context *ev);
+
index 53238662f0cafdbadea900781251948e38258762..96bdafd956d2c39d21e2b9e2257e36b6634a6024 100644 (file)
@@ -274,6 +274,7 @@ static const struct event_ops event_oop_ops = {
        .get_fd_flags   = oop_event_get_fd_flags,
        .set_fd_flags   = oop_event_set_fd_flags,
        .add_timed      = oop_event_add_timed,
+       .add_signal     = common_event_add_signal,
        .loop_once      = oop_event_loop_once,
        .loop_wait      = oop_event_loop_wait,
 };
index 5f4ecba5ca172a0b1930d9e4df44b3c3395bf9fe..ea84353183007fd7c5f4efb8bdbd75c1f1837129 100644 (file)
@@ -197,8 +197,19 @@ static int select_event_loop_select(struct select_event_context *select_ev, stru
                }
        }
 
+       if (select_ev->ev->num_signal_handlers && 
+           common_event_check_signal(select_ev->ev)) {
+               return 0;
+       }
+
        selrtn = select(select_ev->maxfd+1, &r_fds, &w_fds, NULL, tvalp);
 
+       if (selrtn == -1 && errno == EINTR && 
+           select_ev->ev->num_signal_handlers) {
+               common_event_check_signal(select_ev->ev);
+               return 0;
+       }
+
        if (selrtn == -1 && errno == EBADF) {
                /* the socket is dead! this should never
                   happen as the socket should have first been
@@ -279,6 +290,7 @@ static const struct event_ops select_event_ops = {
        .get_fd_flags   = select_event_get_fd_flags,
        .set_fd_flags   = select_event_set_fd_flags,
        .add_timed      = common_event_add_timed,
+       .add_signal     = common_event_add_signal,
        .loop_once      = select_event_loop_once,
        .loop_wait      = select_event_loop_wait,
 };
diff --git a/source4/lib/events/events_signal.c b/source4/lib/events/events_signal.c
new file mode 100644 (file)
index 0000000..85b42ae
--- /dev/null
@@ -0,0 +1,153 @@
+/* 
+   Unix SMB/CIFS implementation.
+
+   common events code for signal events
+
+   Copyright (C) Andrew Tridgell       2007
+   
+   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 2 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, write to the Free Software
+   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+*/
+
+#include "includes.h"
+#include "system/filesys.h"
+#include "system/select.h"
+#include "lib/util/dlinklist.h"
+#include "lib/events/events.h"
+#include "lib/events/events_internal.h"
+
+#define NUM_SIGNALS 64
+
+/*
+  the poor design of signals means that this table must be static global
+*/
+static struct {
+       struct signal_event *sig_handlers[NUM_SIGNALS];
+       uint32_t signal_count[NUM_SIGNALS];
+       uint32_t got_signal;
+       int pipe_hack[2];
+} sig_state;
+
+
+/*
+  signal handler - redirects to registered signals
+*/
+static void signal_handler(int signum)
+{
+       char c = 0;
+       sig_state.signal_count[signum]++;
+       sig_state.got_signal++;
+       /* doesn't matter if this pipe overflows */
+       write(sig_state.pipe_hack[1], &c, 1);
+}
+
+
+/*
+  destroy a signal event
+*/
+static int signal_event_destructor(struct signal_event *se)
+{
+       se->event_ctx->num_signal_handlers--;
+       DLIST_REMOVE(sig_state.sig_handlers[se->signum], se);
+       if (sig_state.sig_handlers[se->signum] == NULL) {
+               signal(se->signum, SIG_DFL);
+       }
+       return 0;
+}
+
+/*
+  this is part of the pipe hack needed to avoid the signal race condition
+*/
+static void signal_pipe_handler(struct event_context *ev, struct fd_event *fde, 
+                               uint16_t flags, void *private)
+{
+       char c[16];
+       /* its non-blocking, doesn't matter if we read too much */
+       read(sig_state.pipe_hack[0], c, sizeof(c));
+}
+
+/*
+  add a signal event
+  return NULL on failure (memory allocation error)
+*/
+struct signal_event *common_event_add_signal(struct event_context *ev, 
+                                           TALLOC_CTX *mem_ctx,
+                                           int signum,
+                                           event_signal_handler_t handler, 
+                                           void *private_data) 
+{
+       struct signal_event *se;
+
+       if (signum >= NUM_SIGNALS) {
+               return NULL;
+       }
+
+       se = talloc(mem_ctx?mem_ctx:ev, struct signal_event);
+       if (se == NULL) return NULL;
+
+       se->event_ctx           = ev;
+       se->handler             = handler;
+       se->private_data        = private_data;
+       se->signum              = signum;
+
+       if (sig_state.sig_handlers[signum] == NULL) {
+               signal(signum, signal_handler);
+       }
+
+       DLIST_ADD(sig_state.sig_handlers[signum], se);
+
+       talloc_set_destructor(se, signal_event_destructor);
+
+       if (ev->pipe_fde == NULL) {
+               if (sig_state.pipe_hack[0] == 0 && 
+                   sig_state.pipe_hack[1] == 0) {
+                       pipe(sig_state.pipe_hack);
+                       set_blocking(sig_state.pipe_hack[0], False);
+                       set_blocking(sig_state.pipe_hack[1], False);
+               }
+               ev->pipe_fde = event_add_fd(ev, ev, sig_state.pipe_hack[0],
+                                           EVENT_FD_READ, signal_pipe_handler, NULL);
+       }
+       ev->num_signal_handlers++;
+
+       return se;
+}
+
+
+/*
+  check if a signal is pending
+  return != 0 if a signal was pending
+*/
+int common_event_check_signal(struct event_context *ev)
+{
+       int i;
+       if (sig_state.got_signal == 0) {
+               return 0;
+       }
+       
+       for (i=0;i<NUM_SIGNALS+1;i++) {
+               uint32_t count = sig_state.signal_count[i];
+               if (count != 0) {
+                       struct signal_event *se, *next;
+                       for (se=sig_state.sig_handlers[i];se;se=next) {
+                               next = se->next;
+                               se->handler(ev, se, i, count, se->private_data);
+                       }
+                       sig_state.signal_count[i] -= count;
+                       sig_state.got_signal -= count;
+               }
+       }
+
+       return 1;
+}
index b0f5259fa7eabafe7eeba6c940ccae37bc8d081b..9c470235d00c1d41d41ac41d3f8221a0500198e9 100644 (file)
@@ -229,8 +229,19 @@ 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)) {
+               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)) {
+                       return 0;
+               }
+       }
+
        if (ret == -1 && errno != EINTR) {
                epoll_fallback_to_select(std_ev, "epoll_wait() failed");
                return -1;
@@ -434,8 +445,19 @@ static int std_event_loop_select(struct std_event_context *std_ev, struct timeva
                }
        }
 
+       if (std_ev->ev->num_signal_handlers && 
+           common_event_check_signal(std_ev->ev)) {
+               return 0;
+       }
+
        selrtn = select(std_ev->maxfd+1, &r_fds, &w_fds, NULL, tvalp);
 
+       if (selrtn == -1 && errno == EINTR && 
+           std_ev->ev->num_signal_handlers) {
+               common_event_check_signal(std_ev->ev);
+               return 0;
+       }
+
        if (selrtn == -1 && errno == EBADF) {
                /* the socket is dead! this should never
                   happen as the socket should have first been
@@ -520,6 +542,7 @@ static const struct event_ops std_event_ops = {
        .get_fd_flags   = std_event_get_fd_flags,
        .set_fd_flags   = std_event_set_fd_flags,
        .add_timed      = common_event_add_timed,
+       .add_signal     = common_event_add_signal,
        .loop_once      = std_event_loop_once,
        .loop_wait      = std_event_loop_wait,
 };