Commit eb8c9bdd authored by Ondřej Surý's avatar Ondřej Surý
Browse files

Make lib/isc/app.c opaque and thread-safe

This work cleans up the API which includes couple of things:

1. Make the isc_appctx_t type fully opaque

2. Protect all access to the isc_app_t members via stdatomics

3. sigwait() is part of POSIX.1, remove dead non-sigwait code

4. Remove unused code: isc_appctx_set{taskmgr,sockmgr,timermgr}
parent 4d30aee3
Pipeline #14807 passed with stages
in 11 minutes and 55 seconds
......@@ -1622,9 +1622,9 @@ main(int argc, char *argv[]) {
fatal("failed to create mctx");
CHECK(isc_appctx_create(mctx, &actx));
CHECK(isc_taskmgr_createinctx(mctx, actx, 1, 0, &taskmgr));
CHECK(isc_socketmgr_createinctx(mctx, actx, &socketmgr));
CHECK(isc_timermgr_createinctx(mctx, actx, &timermgr));
CHECK(isc_taskmgr_createinctx(mctx, 1, 0, &taskmgr));
CHECK(isc_socketmgr_createinctx(mctx, &socketmgr));
CHECK(isc_timermgr_createinctx(mctx, &timermgr));
parse_args(argc, argv);
......
......@@ -278,7 +278,7 @@ rndc_senddone(isc_task_t *task, isc_event_t *event) {
if (sends == 0 && recvs == 0) {
isc_socket_detach(&sock);
isc_task_shutdown(task);
RUNTIME_CHECK(isc_app_shutdown() == ISC_R_SUCCESS);
isc_app_shutdown();
}
}
......@@ -347,7 +347,7 @@ rndc_recvdone(isc_task_t *task, isc_event_t *event) {
if (sends == 0 && recvs == 0) {
isc_socket_detach(&sock);
isc_task_shutdown(task);
RUNTIME_CHECK(isc_app_shutdown() == ISC_R_SUCCESS);
isc_app_shutdown();
}
}
......
......@@ -98,7 +98,7 @@ tick(isc_task_t *task, isc_event_t *event) {
info->ticks++;
if (strcmp(info->name, "1") == 0) {
if (info->ticks == 10) {
RUNTIME_CHECK(isc_app_shutdown() == ISC_R_SUCCESS);
isc_app_shutdown();
} else if (info->ticks >= 15 && info->exiting) {
isc_timer_detach(&info->timer);
isc_task_detach(&info->task);
......
......@@ -635,10 +635,7 @@ LIBS="$PTHREAD_LIBS $LIBS"
CFLAGS="$CFLAGS $PTHREAD_CFLAGS"
CC="$PTHREAD_CC"
#
# We'd like to use sigwait() too
#
AC_CHECK_FUNCS([sigwait pthread_attr_getstacksize pthread_attr_setstacksize])
AC_CHECK_FUNCS([pthread_attr_getstacksize pthread_attr_setstacksize])
AC_ARG_WITH([locktype],
AS_HELP_STRING([--with-locktype=ARG],
......
......@@ -420,13 +420,13 @@ dns_client_create(dns_client_t **clientp, unsigned int options) {
result = isc_app_ctxstart(actx);
if (result != ISC_R_SUCCESS)
goto cleanup;
result = isc_taskmgr_createinctx(mctx, actx, 1, 0, &taskmgr);
result = isc_taskmgr_createinctx(mctx, 1, 0, &taskmgr);
if (result != ISC_R_SUCCESS)
goto cleanup;
result = isc_socketmgr_createinctx(mctx, actx, &socketmgr);
result = isc_socketmgr_createinctx(mctx, &socketmgr);
if (result != ISC_R_SUCCESS)
goto cleanup;
result = isc_timermgr_createinctx(mctx, actx, &timermgr);
result = isc_timermgr_createinctx(mctx, &timermgr);
if (result != ISC_R_SUCCESS)
goto cleanup;
#if 0
......
......@@ -101,15 +101,15 @@ ctxs_init(isc_mem_t **mctxp, isc_appctx_t **actxp,
if (result != ISC_R_SUCCESS)
goto fail;
result = isc_taskmgr_createinctx(*mctxp, *actxp, 1, 0, taskmgrp);
result = isc_taskmgr_createinctx(*mctxp, 1, 0, taskmgrp);
if (result != ISC_R_SUCCESS)
goto fail;
result = isc_socketmgr_createinctx(*mctxp, *actxp, socketmgrp);
result = isc_socketmgr_createinctx(*mctxp, socketmgrp);
if (result != ISC_R_SUCCESS)
goto fail;
result = isc_timermgr_createinctx(*mctxp, *actxp, timermgrp);
result = isc_timermgr_createinctx(*mctxp, timermgrp);
if (result != ISC_R_SUCCESS)
goto fail;
......
......@@ -103,14 +103,7 @@ typedef isc_event_t isc_appevent_t;
* of the isc_app_ routines to work. app implementations must maintain
* all app context invariants.
*/
struct isc_appctx {
unsigned int impmagic;
unsigned int magic;
};
#define ISCAPI_APPCTX_MAGIC ISC_MAGIC('A','a','p','c')
#define ISCAPI_APPCTX_VALID(c) ((c) != NULL && \
(c)->magic == ISCAPI_APPCTX_MAGIC)
struct isc_appctx;
ISC_LANG_BEGINDECLS
......@@ -184,10 +177,10 @@ isc_app_isrunning(void);
*\li false App is not running.
*/
isc_result_t
void
isc_app_ctxshutdown(isc_appctx_t *ctx);
isc_result_t
void
isc_app_shutdown(void);
/*!<
* \brief Request application shutdown.
......@@ -205,13 +198,13 @@ isc_app_shutdown(void);
*\li ISC_R_UNEXPECTED
*/
isc_result_t
void
isc_app_ctxsuspend(isc_appctx_t *ctx);
/*!<
* \brief This has the same behavior as isc_app_ctxsuspend().
*/
isc_result_t
void
isc_app_reload(void);
/*!<
* \brief Request application reload.
......@@ -295,44 +288,6 @@ isc_appctx_destroy(isc_appctx_t **ctxp);
*\li *ctxp == NULL.
*/
void
isc_appctx_settaskmgr(isc_appctx_t *ctx, isc_taskmgr_t *taskmgr);
/*!<
* \brief Associate a task manager with an application context.
*
* This must be done before running tasks within the application context.
*
* Requires:
*\li 'ctx' is a valid application context.
*\li 'taskmgr' is a valid task manager.
*/
void
isc_appctx_setsocketmgr(isc_appctx_t *ctx, isc_socketmgr_t *socketmgr);
/*!<
* \brief Associate a socket manager with an application context.
*
* This must be done before handling socket events within the application
* context.
*
* Requires:
*\li 'ctx' is a valid application context.
*\li 'socketmgr' is a valid socket manager.
*/
void
isc_appctx_settimermgr(isc_appctx_t *ctx, isc_timermgr_t *timermgr);
/*!<
* \brief Associate a socket timer with an application context.
*
* This must be done before handling timer events within the application
* context.
*
* Requires:
*\li 'ctx' is a valid application context.
*\li 'timermgr' is a valid timer manager.
*/
ISC_LANG_ENDDECLS
#endif /* ISC_APP_H */
......@@ -805,8 +805,7 @@ isc_socket_sendto2(isc_socket_t *sock, isc_region_t *region,
/*@}*/
isc_result_t
isc_socketmgr_createinctx(isc_mem_t *mctx, isc_appctx_t *actx,
isc_socketmgr_t **managerp);
isc_socketmgr_createinctx(isc_mem_t *mctx, isc_socketmgr_t **managerp);
isc_result_t
isc_socketmgr_create(isc_mem_t *mctx, isc_socketmgr_t **managerp);
......
......@@ -630,7 +630,7 @@ isc_task_privilege(isc_task_t *task);
*****/
isc_result_t
isc_taskmgr_createinctx(isc_mem_t *mctx, isc_appctx_t *actx,
isc_taskmgr_createinctx(isc_mem_t *mctx,
unsigned int workers, unsigned int default_quantum,
isc_taskmgr_t **managerp);
isc_result_t
......
......@@ -316,8 +316,7 @@ isc_timer_gettype(isc_timer_t *timer);
*/
isc_result_t
isc_timermgr_createinctx(isc_mem_t *mctx, isc_appctx_t *actx,
isc_timermgr_t **managerp);
isc_timermgr_createinctx(isc_mem_t *mctx, isc_timermgr_t **managerp);
isc_result_t
isc_timermgr_create(isc_mem_t *mctx, isc_timermgr_t **managerp);
......
......@@ -1871,7 +1871,7 @@ isc_taskmgr_renderjson(isc_taskmgr_t *mgr0, json_object *tasks) {
isc_result_t
isc_taskmgr_createinctx(isc_mem_t *mctx, isc_appctx_t *actx,
isc_taskmgr_createinctx(isc_mem_t *mctx,
unsigned int workers, unsigned int default_quantum,
isc_taskmgr_t **managerp)
{
......@@ -1880,8 +1880,5 @@ isc_taskmgr_createinctx(isc_mem_t *mctx, isc_appctx_t *actx,
result = isc_taskmgr_create(mctx, workers, default_quantum,
managerp);
if (result == ISC_R_SUCCESS)
isc_appctx_settaskmgr(actx, *managerp);
return (result);
}
......@@ -784,15 +784,11 @@ isc_timermgr_destroy(isc_timermgr_t **managerp) {
}
isc_result_t
isc_timermgr_createinctx(isc_mem_t *mctx, isc_appctx_t *actx,
isc_timermgr_t **managerp)
isc_timermgr_createinctx(isc_mem_t *mctx, isc_timermgr_t **managerp)
{
isc_result_t result;
result = isc_timermgr_create(mctx, managerp);
if (result == ISC_R_SUCCESS)
isc_appctx_settimermgr(actx, *managerp);
return (result);
}
......@@ -27,6 +27,7 @@
#endif
#include <isc/platform.h>
#include <isc/atomic.h>
#include <isc/app.h>
#include <isc/condition.h>
#include <isc/mem.h>
......@@ -48,7 +49,7 @@
* as an event loop dispatching various events.
*/
static pthread_t blockedthread;
static bool is_running;
static atomic_bool is_running;
/*
* The application context of this module. This implementation actually
......@@ -57,72 +58,41 @@ static bool is_running;
#define APPCTX_MAGIC ISC_MAGIC('A', 'p', 'c', 'x')
#define VALID_APPCTX(c) ISC_MAGIC_VALID(c, APPCTX_MAGIC)
typedef struct isc__appctx {
isc_appctx_t common;
struct isc_appctx {
unsigned int magic;
isc_mem_t *mctx;
isc_mutex_t lock;
isc_eventlist_t on_run;
bool shutdown_requested;
bool running;
/*!
* We assume that 'want_shutdown' can be read and written atomically.
*/
bool want_shutdown;
/*
* We assume that 'want_reload' can be read and written atomically.
*/
bool want_reload;
bool blocked;
isc_taskmgr_t *taskmgr;
isc_socketmgr_t *socketmgr;
isc_timermgr_t *timermgr;
isc_eventlist_t on_run;
atomic_bool shutdown_requested;
atomic_bool running;
atomic_bool want_shutdown;
atomic_bool want_reload;
atomic_bool blocked;
isc_mutex_t readylock;
isc_condition_t ready;
} isc__appctx_t;
static isc__appctx_t isc_g_appctx;
isc_condition_t ready;
};
#ifndef HAVE_SIGWAIT
static void
exit_action(int arg) {
UNUSED(arg);
isc_g_appctx.want_shutdown = true;
}
static isc_appctx_t isc_g_appctx;
static void
reload_action(int arg) {
UNUSED(arg);
isc_g_appctx.want_reload = true;
}
#endif
static isc_result_t
handle_signal(int sig, void (*handler)(int)) {
struct sigaction sa;
char strbuf[ISC_STRERRORSIZE];
memset(&sa, 0, sizeof(sa));
sa.sa_handler = handler;
if (sigfillset(&sa.sa_mask) != 0 ||
sigaction(sig, &sa, NULL) < 0) {
char strbuf[ISC_STRERRORSIZE];
strerror_r(errno, strbuf, sizeof(strbuf));
UNEXPECTED_ERROR(__FILE__, __LINE__,
isc_error_fatal(__FILE__, __LINE__,
"handle_signal() %d setup: %s",
sig, strbuf);
return (ISC_R_UNEXPECTED);
}
return (ISC_R_SUCCESS);
}
isc_result_t
isc_app_ctxstart(isc_appctx_t *ctx0) {
isc__appctx_t *ctx = (isc__appctx_t *)ctx0;
isc_result_t result;
isc_app_ctxstart(isc_appctx_t *ctx) {
int presult;
sigset_t sset;
char strbuf[ISC_STRERRORSIZE];
......@@ -133,64 +103,27 @@ isc_app_ctxstart(isc_appctx_t *ctx0) {
* Start an ISC library application.
*/
isc_mutex_init(&ctx->readylock);
isc_mutex_init(&ctx->lock);
isc_mutex_init(&ctx->readylock);
isc_condition_init(&ctx->ready);
isc_mutex_init(&ctx->lock);
ISC_LIST_INIT(ctx->on_run);
ctx->shutdown_requested = false;
ctx->running = false;
ctx->want_shutdown = false;
ctx->want_reload = false;
ctx->blocked = false;
#ifndef HAVE_SIGWAIT
/*
* Install do-nothing handlers for SIGINT and SIGTERM.
*
* We install them now because BSDI 3.1 won't block
* the default actions, regardless of what we do with
* pthread_sigmask().
*/
result = handle_signal(SIGINT, exit_action);
if (result != ISC_R_SUCCESS)
goto cleanup;
result = handle_signal(SIGTERM, exit_action);
if (result != ISC_R_SUCCESS)
goto cleanup;
#endif
atomic_init(&ctx->shutdown_requested, false);
atomic_init(&ctx->running, false);
atomic_init(&ctx->want_shutdown, false);
atomic_init(&ctx->want_reload, false);
atomic_init(&ctx->blocked, false);
/*
* Always ignore SIGPIPE.
*/
result = handle_signal(SIGPIPE, SIG_IGN);
if (result != ISC_R_SUCCESS)
goto cleanup;
handle_signal(SIGPIPE, SIG_IGN);
/*
* On Solaris 2, delivery of a signal whose action is SIG_IGN
* will not cause sigwait() to return. We may have inherited
* unexpected actions for SIGHUP, SIGINT, and SIGTERM from our parent
* process (e.g, Solaris cron). Set an action of SIG_DFL to make
* sure sigwait() works as expected. Only do this for SIGTERM and
* SIGINT if we don't have sigwait(), since a different handler is
* installed above.
*/
result = handle_signal(SIGHUP, SIG_DFL);
if (result != ISC_R_SUCCESS)
goto cleanup;
#ifdef HAVE_SIGWAIT
result = handle_signal(SIGTERM, SIG_DFL);
if (result != ISC_R_SUCCESS)
goto cleanup;
result = handle_signal(SIGINT, SIG_DFL);
if (result != ISC_R_SUCCESS)
goto cleanup;
#endif
handle_signal(SIGHUP, SIG_DFL);
handle_signal(SIGTERM, SIG_DFL);
handle_signal(SIGINT, SIG_DFL);
/*
* Block SIGHUP, SIGINT, SIGTERM.
......@@ -206,61 +139,45 @@ isc_app_ctxstart(isc_appctx_t *ctx0) {
sigaddset(&sset, SIGINT) != 0 ||
sigaddset(&sset, SIGTERM) != 0) {
strerror_r(errno, strbuf, sizeof(strbuf));
UNEXPECTED_ERROR(__FILE__, __LINE__,
isc_error_fatal(__FILE__, __LINE__,
"isc_app_start() sigsetops: %s", strbuf);
result = ISC_R_UNEXPECTED;
goto cleanup;
}
presult = pthread_sigmask(SIG_BLOCK, &sset, NULL);
if (presult != 0) {
strerror_r(presult, strbuf, sizeof(strbuf));
UNEXPECTED_ERROR(__FILE__, __LINE__,
isc_error_fatal(__FILE__, __LINE__,
"isc_app_start() pthread_sigmask: %s",
strbuf);
result = ISC_R_UNEXPECTED;
goto cleanup;
}
return (ISC_R_SUCCESS);
cleanup:
(void)isc_condition_destroy(&ctx->ready);
(void)isc_mutex_destroy(&ctx->readylock);
return (result);
}
isc_result_t
isc_app_start(void) {
isc_g_appctx.common.impmagic = APPCTX_MAGIC;
isc_g_appctx.common.magic = ISCAPI_APPCTX_MAGIC;
isc_g_appctx.magic = APPCTX_MAGIC;
isc_g_appctx.mctx = NULL;
/* The remaining members will be initialized in ctxstart() */
return (isc_app_ctxstart((isc_appctx_t *)&isc_g_appctx));
return (isc_app_ctxstart(&isc_g_appctx));
}
isc_result_t
isc_app_onrun(isc_mem_t *mctx, isc_task_t *task, isc_taskaction_t action,
void *arg)
{
return (isc_app_ctxonrun((isc_appctx_t *)&isc_g_appctx, mctx,
task, action, arg));
return (isc_app_ctxonrun(&isc_g_appctx, mctx, task, action, arg));
}
isc_result_t
isc_app_ctxonrun(isc_appctx_t *ctx0, isc_mem_t *mctx, isc_task_t *task,
isc_app_ctxonrun(isc_appctx_t *ctx, isc_mem_t *mctx, isc_task_t *task,
isc_taskaction_t action, void *arg)
{
isc__appctx_t *ctx = (isc__appctx_t *)ctx0;
isc_event_t *event;
isc_task_t *cloned_task = NULL;
isc_result_t result;
LOCK(&ctx->lock);
if (ctx->running) {
result = ISC_R_ALREADYRUNNING;
goto unlock;
if (atomic_load_acquire(&ctx->running)) {
return (ISC_R_ALREADYRUNNING);
}
/*
......@@ -272,42 +189,34 @@ isc_app_ctxonrun(isc_appctx_t *ctx0, isc_mem_t *mctx, isc_task_t *task,
action, arg, sizeof(*event));
if (event == NULL) {
isc_task_detach(&cloned_task);
result = ISC_R_NOMEMORY;
goto unlock;
return (ISC_R_NOMEMORY);
}
LOCK(&ctx->lock);
ISC_LIST_APPEND(ctx->on_run, event, ev_link);
result = ISC_R_SUCCESS;
unlock:
UNLOCK(&ctx->lock);
return (result);
return (ISC_R_SUCCESS);
}
isc_result_t
isc_app_ctxrun(isc_appctx_t *ctx0) {
isc__appctx_t *ctx = (isc__appctx_t *)ctx0;
int result;
isc_app_ctxrun(isc_appctx_t *ctx) {
isc_event_t *event, *next_event;
isc_task_t *task;
sigset_t sset;
char strbuf[ISC_STRERRORSIZE];
#ifdef HAVE_SIGWAIT
int sig;
#endif /* HAVE_SIGWAIT */
bool exp_false = false;
bool exp_true = true;
REQUIRE(VALID_APPCTX(ctx));
LOCK(&ctx->lock);
if (!ctx->running) {
ctx->running = true;
if (atomic_compare_exchange_weak_acq_rel(
&ctx->running, &exp_false, true) == true)
{
/*
* Post any on-run events (in FIFO order).
*/
LOCK(&ctx->lock);
for (event = ISC_LIST_HEAD(ctx->on_run);
event != NULL;
event = next_event) {
......@@ -317,17 +226,15 @@ isc_app_ctxrun(isc_appctx_t *ctx0) {
event->ev_sender = NULL;
isc_task_sendanddetach(&task, &event);
}
UNLOCK(&ctx->lock);
}
UNLOCK(&ctx->lock);
/*
* BIND9 internal tools using multiple contexts do not
* rely on signal.
*/
if (isc_bind9 && ctx != &isc_g_appctx)
* rely on signal. */
if (isc_bind9 && ctx != &isc_g_appctx) {
return (ISC_R_SUCCESS);
}
/*
* There is no danger if isc_app_shutdown() is called before we
......@@ -335,8 +242,7 @@ isc_app_ctxrun(isc_appctx_t *ctx0) {
* simply be made pending and we will get it when we call
* sigwait().
*/
while (!ctx->want_shutdown) {
#ifdef HAVE_SIGWAIT
while (atomic_load_acquire(&ctx->want_shutdown) == false) {
if (isc_bind9) {
/*
* BIND9 internal; single context:
......@@ -346,88 +252,56 @@ isc_app_ctxrun(isc_appctx_t *ctx0) {
sigaddset(&sset, SIGHUP) != 0 ||
sigaddset(&sset, SIGINT) != 0 ||
sigaddset(&sset, SIGTERM) != 0) {
char strbuf[ISC_STRERRORSIZE];
strerror_r(errno, strbuf, sizeof(strbuf));
UNEXPECTED_ERROR(__FILE__, __LINE__,
"isc_app_run() sigsetops: %s",
strbuf);
return (ISC_R_UNEXPECTED);
isc_error_fatal(__FILE__, __LINE__,
"isc_app_run() sigsetops: %s",
strbuf);
}
result = sigwait(&sset, &sig);
if (result == 0) {
if (sig == SIGINT || sig == SIGTERM)
ctx->want_shutdown = true;
else if (sig == SIGHUP)
ctx->want_reload = true;
if (sigwait(&sset, &sig) == 0) {
switch (sig) {
case SIGINT:
case SIGTERM:
atomic_store_release(
&ctx->want_shutdown, true);
break;
case SIGHUP:
atomic_store_release(
&ctx->want_reload, true);
break;
default:
INSIST(0);
ISC_UNREACHABLE();
}
}
} else {
/*
* External, or BIND9 using multiple contexts:
* wait until woken up.
*/
LOCK(&ctx->readylock);