[MEDIUM] signals: add support for registering functions and tasks
The two new functions below make it possible to register any number
of functions or tasks to a system signal. They will be called in the
registration order when the signal is received.
struct sig_handler *signal_register_fct(int sig, void (*fct)(struct sig_handler *), int arg);
struct sig_handler *signal_register_task(int sig, struct task *task, int reason);
diff --git a/include/proto/signal.h b/include/proto/signal.h
index 2734827..5b5a64a 100644
--- a/include/proto/signal.h
+++ b/include/proto/signal.h
@@ -1,7 +1,8 @@
/*
+ * include/proto/signal.h
* Asynchronous signal delivery functions.
*
- * Copyright 2000-2009 Willy Tarreau <w@1wt.eu>
+ * Copyright 2000-2010 Willy Tarreau <w@1wt.eu>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
@@ -16,14 +17,25 @@
extern int signal_queue_len;
extern struct signal_descriptor signal_state[];
+extern struct pool_head *pool2_sig_handlers;
-void signal_init();
-void signal_handler(int sig);
-void signal_register(int sig, void (*handler)(int));
void __signal_process_queue();
+int signal_init();
+void deinit_signals();
+struct sig_handler *signal_register_fct(int sig, void (*fct)(struct sig_handler *), int arg);
+struct sig_handler *signal_register_task(int sig, struct task *task, int reason);
+void signal_unregister_handler(struct sig_handler *handler);
+void signal_unregister_target(int sig, void *target);
static inline void signal_process_queue()
{
if (unlikely(signal_queue_len > 0))
__signal_process_queue();
}
+
+/*
+ * Local variables:
+ * c-indent-level: 8
+ * c-basic-offset: 8
+ * End:
+ */
diff --git a/include/proto/task.h b/include/proto/task.h
index 0cfe28f..2c02ca6 100644
--- a/include/proto/task.h
+++ b/include/proto/task.h
@@ -1,23 +1,23 @@
/*
- include/proto/task.h
- Functions for task management.
-
- Copyright (C) 2000-2009 Willy Tarreau - w@1wt.eu
-
- 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, version 2.1
- exclusively.
-
- 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, write to the Free Software
- Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
-*/
+ * include/proto/task.h
+ * Functions for task management.
+ *
+ * Copyright (C) 2000-2010 Willy Tarreau - w@1wt.eu
+ *
+ * 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, version 2.1
+ * exclusively.
+ *
+ * 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, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
#ifndef _PROTO_TASK_H
#define _PROTO_TASK_H
diff --git a/include/types/signal.h b/include/types/signal.h
index b863d23..598001e 100644
--- a/include/types/signal.h
+++ b/include/types/signal.h
@@ -1,7 +1,8 @@
/*
+ * include/types/signal.h
* Asynchronous signal delivery functions descriptors.
*
- * Copyright 2000-2009 Willy Tarreau <w@1wt.eu>
+ * Copyright 2000-2010 Willy Tarreau <w@1wt.eu>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
@@ -10,11 +11,39 @@
*
*/
+#ifndef _TYPES_SIGNAL_H
+#define _TYPES_SIGNAL_H
+
+
#include <signal.h>
#include <common/config.h>
+#include <common/mini-clist.h>
#include <common/standard.h>
+/* flags for -> flags */
+#define SIG_F_ONE_SHOOT 0x0001 /* unregister handler before calling it */
+#define SIG_F_TYPE_FCT 0x0002 /* handler is a function + arg */
+#define SIG_F_TYPE_TASK 0x0004 /* handler is a task + reason */
+
+/* those are highly dynamic and stored in pools */
+struct sig_handler {
+ struct list list;
+ void *handler; /* function to call or task to wake up */
+ int arg; /* arg to pass to function, or signals*/
+ int flags; /* SIG_F_* */
+};
+
+/* one per signal */
struct signal_descriptor {
- int count; /* number of times raised */
- void (*handler)(int sig);
+ int count; /* number of times raised */
+ struct list handlers; /* sig_handler */
};
+
+#endif /* _TYPES_SIGNAL_H */
+
+/*
+ * Local variables:
+ * c-indent-level: 8
+ * c-basic-offset: 8
+ * End:
+ */
diff --git a/include/types/task.h b/include/types/task.h
index 41f889c..405404b 100644
--- a/include/types/task.h
+++ b/include/types/task.h
@@ -1,23 +1,23 @@
/*
- include/types/task.h
- Macros, variables and structures for task management.
-
- Copyright (C) 2000-2009 Willy Tarreau - w@1wt.eu
-
- 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, version 2.1
- exclusively.
-
- 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, write to the Free Software
- Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
-*/
+ * include/types/task.h
+ * Macros, variables and structures for task management.
+ *
+ * Copyright (C) 2000-2010 Willy Tarreau - w@1wt.eu
+ *
+ * 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, version 2.1
+ * exclusively.
+ *
+ * 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, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
#ifndef _TYPES_TASK_H
#define _TYPES_TASK_H
@@ -44,6 +44,12 @@
TASK_WOKEN_IO|TASK_WOKEN_SIGNAL|TASK_WOKEN_MSG| \
TASK_WOKEN_RES)
+/* Additional wakeup info may be passed in the state by lef-shifting the value
+ * by this number of bits. Not more than 8 bits are guaranteed to be delivered.
+ * System signals may use that too.
+ */
+#define TASK_REASON_SHIFT 8
+
/* The base for all tasks */
struct task {
struct eb32_node wq; /* ebtree node used to hold the task in the wait queue */
diff --git a/src/haproxy.c b/src/haproxy.c
index ece9526..d9c3b6a 100644
--- a/src/haproxy.c
+++ b/src/haproxy.c
@@ -246,17 +246,17 @@
/*
* upon SIGUSR1, let's have a soft stop.
*/
-void sig_soft_stop(int sig)
+void sig_soft_stop(struct sig_handler *sh)
{
soft_stop();
+ signal_unregister_handler(sh);
pool_gc2();
- signal_register(sig, SIG_IGN);
}
/*
* upon SIGTTOU, we pause everything
*/
-void sig_pause(int sig)
+void sig_pause(struct sig_handler *sh)
{
pause_proxies();
pool_gc2();
@@ -265,7 +265,7 @@
/*
* upon SIGTTIN, let's have a soft stop.
*/
-void sig_listen(int sig)
+void sig_listen(struct sig_handler *sh)
{
listen_proxies();
}
@@ -273,7 +273,7 @@
/*
* this function dumps every server's state when the process receives SIGHUP.
*/
-void sig_dump_state(int sig)
+void sig_dump_state(struct sig_handler *sh)
{
struct proxy *p = proxy;
@@ -319,70 +319,13 @@
}
}
-void dump(int sig)
+void dump(struct sig_handler *sh)
{
-#if 0
- struct task *t;
- struct session *s;
- struct rb_node *node;
-
- for(node = rb_first(&wait_queue[0]);
- node != NULL; node = rb_next(node)) {
- t = rb_entry(node, struct task, rb_node);
- s = t->context;
- qfprintf(stderr,"[dump] wq: task %p, still %ld ms, "
- "cli=%d, srv=%d, req=%d, rep=%d\n",
- s, tv_ms_remain(&now, &t->expire),
- s->si[0].state,
- s->si[1].state,
- s->req->l, s->rep?s->rep->l:0);
- }
-#endif
/* dump memory usage then free everything possible */
dump_pools();
pool_gc2();
-}
-
-#ifdef DEBUG_MEMORY
-static void fast_stop(void)
-{
- struct proxy *p;
- p = proxy;
- while (p) {
- p->grace = 0;
- p = p->next;
- }
- soft_stop();
-}
-
-void sig_int(int sig)
-{
- /* This would normally be a hard stop,
- but we want to be sure about deallocation,
- and so on, so we do a soft stop with
- 0 GRACE time
- */
- fast_stop();
- pool_gc2();
- /* If we are killed twice, we decide to die */
- signal_register(sig, SIG_DFL);
}
-void sig_term(int sig)
-{
- /* This would normally be a hard stop,
- but we want to be sure about deallocation,
- and so on, so we do a soft stop with
- 0 GRACE time
- */
- fast_stop();
- pool_gc2();
- /* If we are killed twice, we decide to die */
- signal_register(sig, SIG_DFL);
-}
-#endif
-
-
/*
* This function initializes all the necessary variables. It only returns
* if everything is OK. If something fails, it exits.
@@ -726,6 +669,7 @@
struct uri_auth *uap, *ua = NULL;
int i;
+ deinit_signals();
while (p) {
free(p->id);
free(p->check_req);
@@ -924,6 +868,7 @@
pool_destroy2(pool2_capture);
pool_destroy2(pool2_appsess);
pool_destroy2(pool2_pendconn);
+ pool_destroy2(pool2_sig_handlers);
if (have_appsession) {
pool_destroy2(apools.serverid);
@@ -931,7 +876,6 @@
}
deinit_pollers();
-
} /* end deinit() */
/* sends the signal <sig> to all pids found in <oldpids>. Returns the number of
@@ -991,19 +935,15 @@
FILE *pidfile = NULL;
init(argc, argv);
- signal_register(SIGQUIT, dump);
- signal_register(SIGUSR1, sig_soft_stop);
- signal_register(SIGHUP, sig_dump_state);
-#ifdef DEBUG_MEMORY
- signal_register(SIGINT, sig_int);
- signal_register(SIGTERM, sig_term);
-#endif
+ signal_register_fct(SIGQUIT, dump, SIGQUIT);
+ signal_register_fct(SIGUSR1, sig_soft_stop, SIGUSR1);
+ signal_register_fct(SIGHUP, sig_dump_state, SIGHUP);
/* Always catch SIGPIPE even on platforms which define MSG_NOSIGNAL.
* Some recent FreeBSD setups report broken pipes, and MSG_NOSIGNAL
* was defined there, so let's stay on the safe side.
*/
- signal(SIGPIPE, SIG_IGN);
+ signal_register_fct(SIGPIPE, NULL, 0);
/* We will loop at most 100 times with 10 ms delay each time.
* That's at most 1 second. We only send a signal to old pids
@@ -1061,8 +1001,8 @@
}
/* prepare pause/play signals */
- signal_register(SIGTTOU, sig_pause);
- signal_register(SIGTTIN, sig_listen);
+ signal_register_fct(SIGTTOU, sig_pause, SIGTTOU);
+ signal_register_fct(SIGTTIN, sig_listen, SIGTTIN);
/* MODE_QUIET can inhibit alerts and warnings below this line */
diff --git a/src/signal.c b/src/signal.c
index 9825c0d..746ae9e 100644
--- a/src/signal.c
+++ b/src/signal.c
@@ -1,7 +1,7 @@
/*
* Asynchronous signal delivery functions.
*
- * Copyright 2000-2009 Willy Tarreau <w@1wt.eu>
+ * Copyright 2000-2010 Willy Tarreau <w@1wt.eu>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
@@ -15,6 +15,7 @@
#include <proto/signal.h>
#include <proto/log.h>
+#include <proto/task.h>
/* Principle : we keep an in-order list of the first occurrence of all received
* signals. All occurrences of a same signal are grouped though. The signal
@@ -26,22 +27,16 @@
int signal_queue_len; /* length of signal queue, <= MAX_SIGNAL (1 entry per signal max) */
int signal_queue[MAX_SIGNAL]; /* in-order queue of received signals */
struct signal_descriptor signal_state[MAX_SIGNAL];
+struct pool_head *pool2_sig_handlers = NULL;
sigset_t blocked_sig;
-void signal_init()
+/* Common signal handler, used by all signals. Received signals are queued. */
+static void signal_handler(int sig)
{
- signal_queue_len = 0;
- memset(signal_queue, 0, sizeof(signal_queue));
- memset(signal_state, 0, sizeof(signal_state));
- sigfillset(&blocked_sig);
-}
-
-void signal_handler(int sig)
-{
- if (sig < 0 || sig > MAX_SIGNAL || !signal_state[sig].handler) {
+ if (sig < 0 || sig > MAX_SIGNAL) {
/* unhandled signal */
- qfprintf(stderr, "Received unhandled signal %d. Signal has been disabled.\n", sig);
signal(sig, SIG_IGN);
+ qfprintf(stderr, "Received unhandled signal %d. Signal has been disabled.\n", sig);
return;
}
@@ -56,33 +51,6 @@
signal(sig, signal_handler); /* re-arm signal */
}
-/* Register a handler for signal <sig>. Set it to NULL, SIG_DFL or SIG_IGN to
- * remove the handler. The signal's queue is flushed and the signal is really
- * registered (or unregistered) for the process. The interface is the same as
- * for standard signal delivery, except that the handler does not need to rearm
- * the signal itself (it can disable it however).
- */
-void signal_register(int sig, void (*handler)(int))
-{
- if (sig < 0 || sig > MAX_SIGNAL) {
- qfprintf(stderr, "Failed to register signal %d : out of range [0..%d].\n", sig, MAX_SIGNAL);
- return;
- }
-
- signal_state[sig].count = 0;
- if (handler == NULL)
- handler = SIG_IGN;
-
- if (handler != SIG_IGN && handler != SIG_DFL) {
- signal_state[sig].handler = handler;
- signal(sig, signal_handler);
- }
- else {
- signal_state[sig].handler = NULL;
- signal(sig, handler);
- }
-}
-
/* Call handlers of all pending signals and clear counts and queue length. The
* handlers may unregister themselves by calling signal_register() while they
* are called, just like it is done with normal signal handlers.
@@ -102,8 +70,13 @@
sig = signal_queue[cur_pos];
desc = &signal_state[sig];
if (desc->count) {
- if (desc->handler)
- desc->handler(sig);
+ struct sig_handler *sh, *shb;
+ list_for_each_entry_safe(sh, shb, &desc->handlers, list) {
+ if ((sh->flags & SIG_F_TYPE_FCT) && sh->handler)
+ ((void (*)(struct sig_handler *))sh->handler)(sh);
+ else if ((sh->flags & SIG_F_TYPE_TASK) && sh->handler)
+ task_wakeup(sh->handler, sh->arg | TASK_WOKEN_SIGNAL);
+ }
desc->count = 0;
}
}
@@ -112,3 +85,126 @@
/* restore signal delivery */
sigprocmask(SIG_SETMASK, &old_sig, NULL);
}
+
+/* perform minimal intializations, report 0 in case of error, 1 if OK. */
+int signal_init()
+{
+ int sig;
+
+ signal_queue_len = 0;
+ memset(signal_queue, 0, sizeof(signal_queue));
+ memset(signal_state, 0, sizeof(signal_state));
+ sigfillset(&blocked_sig);
+ for (sig = 0; sig < MAX_SIGNAL; sig++)
+ LIST_INIT(&signal_state[sig].handlers);
+
+ pool2_sig_handlers = create_pool("sig_handlers", sizeof(struct sig_handler), MEM_F_SHARED);
+ return pool2_sig_handlers != NULL;
+}
+
+/* releases all registered signal handlers */
+void deinit_signals()
+{
+ int sig;
+ struct sig_handler *sh, *shb;
+
+ for (sig = 0; sig < MAX_SIGNAL; sig++) {
+ signal(sig, SIG_DFL);
+ list_for_each_entry_safe(sh, shb, &signal_state[sig].handlers, list) {
+ LIST_DEL(&sh->list);
+ pool_free2(pool2_sig_handlers, sh);
+ }
+ }
+}
+
+/* Register a function and an integer argument on a signal. A pointer to the
+ * newly allocated sig_handler is returned, or NULL in case of any error. The
+ * caller is responsible for unregistering the function when not used anymore.
+ * Note that passing a NULL as the function pointer enables interception of the
+ * signal without processing, which is identical to SIG_IGN.
+ */
+struct sig_handler *signal_register_fct(int sig, void (*fct)(struct sig_handler *), int arg)
+{
+ struct sig_handler *sh;
+
+ if (sig < 0 || sig > MAX_SIGNAL)
+ return NULL;
+
+ signal(sig, signal_handler);
+
+ if (!fct)
+ return NULL;
+
+ sh = pool_alloc2(pool2_sig_handlers);
+ if (!sh)
+ return NULL;
+
+ sh->handler = fct;
+ sh->arg = arg;
+ sh->flags = SIG_F_TYPE_FCT;
+ LIST_ADDQ(&signal_state[sig].handlers, &sh->list);
+ return sh;
+}
+
+/* Register a task and a wake-up reason on a signal. A pointer to the newly
+ * allocated sig_handler is returned, or NULL in case of any error. The caller
+ * is responsible for unregistering the task when not used anymore. Note that
+ * passing a NULL as the task pointer enables interception of the signal
+ * without processing, which is identical to SIG_IGN.
+ */
+struct sig_handler *signal_register_task(int sig, struct task *task, int reason)
+{
+ struct sig_handler *sh;
+
+ if (sig < 0 || sig > MAX_SIGNAL)
+ return NULL;
+
+ signal(sig, signal_handler);
+
+ if (!task)
+ return NULL;
+
+ sh = pool_alloc2(pool2_sig_handlers);
+ if (!sh)
+ return NULL;
+
+ sh->handler = task;
+ sh->arg = reason & ~TASK_WOKEN_ANY;
+ sh->flags = SIG_F_TYPE_TASK;
+ LIST_ADDQ(&signal_state[sig].handlers, &sh->list);
+ return sh;
+}
+
+/* Immediately unregister a handler so that no further signals may be delivered
+ * to it. The struct is released so the caller may not reference it anymore.
+ */
+void signal_unregister_handler(struct sig_handler *handler)
+{
+ LIST_DEL(&handler->list);
+ pool_free2(pool2_sig_handlers, handler);
+}
+
+/* Immediately unregister a handler so that no further signals may be delivered
+ * to it. The handler struct does not need to be known, only the function or
+ * task pointer. This method is expensive because it scans all the list, so it
+ * should only be used for rare cases (eg: exit). The struct is released so the
+ * caller may not reference it anymore.
+ */
+void signal_unregister_target(int sig, void *target)
+{
+ struct sig_handler *sh, *shb;
+
+ if (sig < 0 || sig > MAX_SIGNAL)
+ return;
+
+ if (!target)
+ return;
+
+ list_for_each_entry_safe(sh, shb, &signal_state[sig].handlers, list) {
+ if (sh->handler == target) {
+ LIST_DEL(&sh->list);
+ pool_free2(pool2_sig_handlers, sh);
+ break;
+ }
+ }
+}