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authorAndrew Tridgell <tridge@samba.org>2007-01-21 10:32:39 +0000
committerGerald (Jerry) Carter <jerry@samba.org>2007-10-10 14:43:55 -0500
commitcf8eef4ad88af40d2cf147686c1877cd380b452c (patch)
treecab75b7549dde223cbb1ff6a185c9f7ce7a65b87 /source4/lib/events
parentc6174d5d6f9b2cfc29a1886a79ae72b5ab764c55 (diff)
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r20930: use sigaction() instead of signal()
add support for sa_flags argument to event_add_signal(). These are passed to sigaction(). Special handling is provided for SA_RESETHAND (which tells the event system to remove the handler after the signal) and SA_SIGINFO which allows the siginfo structure to be received per signal (This used to be commit 1bb10b6cf7d717ad21834e73a4ca4b22b5fb6f0a)
Diffstat (limited to 'source4/lib/events')
-rw-r--r--source4/lib/events/events.c6
-rw-r--r--source4/lib/events/events.h4
-rw-r--r--source4/lib/events/events_internal.h4
-rw-r--r--source4/lib/events/events_signal.c84
4 files changed, 87 insertions, 11 deletions
diff --git a/source4/lib/events/events.c b/source4/lib/events/events.c
index 2a6da1370f..e2d5b4c397 100644
--- a/source4/lib/events/events.c
+++ b/source4/lib/events/events.c
@@ -241,14 +241,18 @@ struct timed_event *event_add_timed(struct event_context *ev, TALLOC_CTX *mem_ct
/*
add a signal event
+
+ sa_flags are flags to sigaction(2)
+
return NULL on failure
*/
struct signal_event *event_add_signal(struct event_context *ev, TALLOC_CTX *mem_ctx,
int signum,
+ int sa_flags,
event_signal_handler_t handler,
void *private_data)
{
- return ev->ops->add_signal(ev, mem_ctx, signum, handler, private_data);
+ return ev->ops->add_signal(ev, mem_ctx, signum, sa_flags, handler, private_data);
}
/*
diff --git a/source4/lib/events/events.h b/source4/lib/events/events.h
index eee7a5e470..4177087fb7 100644
--- a/source4/lib/events/events.h
+++ b/source4/lib/events/events.h
@@ -36,7 +36,7 @@ typedef void (*event_fd_handler_t)(struct event_context *, struct fd_event *,
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 *);
+ int , int, void *, void *);
typedef void (*event_aio_handler_t)(struct event_context *, struct aio_event *,
int, void *);
@@ -54,7 +54,7 @@ struct timed_event *event_add_timed(struct event_context *ev, TALLOC_CTX *mem_ct
void *private);
struct signal_event *event_add_signal(struct event_context *ev, TALLOC_CTX *mem_ctx,
- int signum,
+ int signum, int sa_flags,
event_signal_handler_t handler,
void *private);
diff --git a/source4/lib/events/events_internal.h b/source4/lib/events/events_internal.h
index 0b8de12a35..39fade2fdb 100644
--- a/source4/lib/events/events_internal.h
+++ b/source4/lib/events/events_internal.h
@@ -50,7 +50,7 @@ struct event_ops {
/* signal functions */
struct signal_event *(*add_signal)(struct event_context *ev,
TALLOC_CTX *mem_ctx,
- int signum,
+ int signum, int sa_flags,
event_signal_handler_t handler,
void *private_data);
@@ -89,6 +89,7 @@ struct signal_event {
event_signal_handler_t handler;
void *private_data;
int signum;
+ int sa_flags;
};
/* aio event is private to the aio backend */
@@ -122,6 +123,7 @@ 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,
+ int sa_flags,
event_signal_handler_t handler,
void *private_data);
int common_event_check_signal(struct event_context *ev);
diff --git a/source4/lib/events/events_signal.c b/source4/lib/events/events_signal.c
index 85b42ae4ab..e1a50e058f 100644
--- a/source4/lib/events/events_signal.c
+++ b/source4/lib/events/events_signal.c
@@ -29,14 +29,22 @@
#define NUM_SIGNALS 64
+/* maximum number of SA_SIGINFO signals to hold in the queue */
+#define SA_INFO_QUEUE_COUNT 10
+
/*
the poor design of signals means that this table must be static global
*/
static struct {
struct signal_event *sig_handlers[NUM_SIGNALS];
+ struct sigaction oldact[NUM_SIGNALS];
uint32_t signal_count[NUM_SIGNALS];
uint32_t got_signal;
int pipe_hack[2];
+#ifdef SA_SIGINFO
+ /* with SA_SIGINFO we get quite a lot of info per signal */
+ siginfo_t sig_info[NUM_SIGNALS][SA_INFO_QUEUE_COUNT];
+#endif
} sig_state;
@@ -52,6 +60,27 @@ static void signal_handler(int signum)
write(sig_state.pipe_hack[1], &c, 1);
}
+#ifdef SA_SIGINFO
+/*
+ signal handler with SA_SIGINFO - redirects to registered signals
+*/
+static void signal_handler_info(int signum, siginfo_t *info, void *uctx)
+{
+ sig_state.sig_info[signum][sig_state.signal_count[signum]] = *info;
+
+ signal_handler(signum);
+
+ /* handle SA_SIGINFO */
+ if (sig_state.signal_count[signum] == SA_INFO_QUEUE_COUNT) {
+ /* we've filled the info array - block this signal until
+ these ones are delivered */
+ sigset_t set;
+ sigemptyset(&set);
+ sigaddset(&set, signum);
+ sigprocmask(SIG_BLOCK, &set, NULL);
+ }
+}
+#endif
/*
destroy a signal event
@@ -61,7 +90,8 @@ 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);
+ /* restore old handler, if any */
+ sigaction(se->signum, &sig_state.oldact[se->signum], NULL);
}
return 0;
}
@@ -82,10 +112,11 @@ static void signal_pipe_handler(struct event_context *ev, struct fd_event *fde,
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)
+ TALLOC_CTX *mem_ctx,
+ int signum,
+ int sa_flags,
+ event_signal_handler_t handler,
+ void *private_data)
{
struct signal_event *se;
@@ -100,15 +131,32 @@ struct signal_event *common_event_add_signal(struct event_context *ev,
se->handler = handler;
se->private_data = private_data;
se->signum = signum;
+ se->sa_flags = sa_flags;
+ /* only install a signal handler if not already installed */
if (sig_state.sig_handlers[signum] == NULL) {
- signal(signum, signal_handler);
+ struct sigaction act;
+ ZERO_STRUCT(act);
+ act.sa_handler = signal_handler;
+ act.sa_flags = sa_flags;
+#ifdef SA_SIGINFO
+ if (sa_flags & SA_SIGINFO) {
+ act.sa_handler = NULL;
+ act.sa_sigaction = signal_handler_info;
+ }
+#endif
+ if (sigaction(signum, &act, &sig_state.oldact[signum]) == -1) {
+ talloc_free(se);
+ return NULL;
+ }
}
DLIST_ADD(sig_state.sig_handlers[signum], se);
talloc_set_destructor(se, signal_event_destructor);
+ /* we need to setup the pipe hack handler if not already
+ setup */
if (ev->pipe_fde == NULL) {
if (sig_state.pipe_hack[0] == 0 &&
sig_state.pipe_hack[1] == 0) {
@@ -142,7 +190,29 @@ int common_event_check_signal(struct event_context *ev)
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);
+#ifdef SA_SIGINFO
+ if (se->sa_flags & SA_SIGINFO) {
+ int j;
+ for (j=0;j<count;j++) {
+ se->handler(ev, se, i, 1,
+ (void*)&sig_state.sig_info[i][j],
+ se->private_data);
+ }
+ if (count == SA_INFO_QUEUE_COUNT) {
+ /* we'd filled the queue, unblock the
+ signal now */
+ sigset_t set;
+ sigemptyset(&set);
+ sigaddset(&set, i);
+ sigprocmask(SIG_UNBLOCK, &set, NULL);
+ }
+ continue;
+ }
+#endif
+ se->handler(ev, se, i, count, NULL, se->private_data);
+ if (se->sa_flags & SA_RESETHAND) {
+ talloc_free(se);
+ }
}
sig_state.signal_count[i] -= count;
sig_state.got_signal -= count;