/* Copyright Joyent, Inc. and other Node contributors. All rights reserved.
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to
* deal in the Software without restriction, including without limitation the
* rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
* sell copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
* IN THE SOFTWARE.
*/
#include <assert.h>
#include <signal.h>
#include "uv.h"
#include "internal.h"
#include "handle-inl.h"
#include "req-inl.h"
RB_HEAD(uv_signal_tree_s, uv_signal_s);
static struct uv_signal_tree_s uv__signal_tree = RB_INITIALIZER(uv__signal_tree);
static CRITICAL_SECTION uv__signal_lock;
static BOOL WINAPI uv__signal_control_handler(DWORD type);
int uv__signal_start(uv_signal_t* handle,
uv_signal_cb signal_cb,
int signum,
int oneshot);
void uv_signals_init(void) {
InitializeCriticalSection(&uv__signal_lock);
if (!SetConsoleCtrlHandler(uv__signal_control_handler, TRUE))
abort();
}
void uv__signal_cleanup(void) {
/* TODO(bnoordhuis) Undo effects of uv_signal_init()? */
}
static int uv__signal_compare(uv_signal_t* w1, uv_signal_t* w2) {
/* Compare signums first so all watchers with the same signnum end up
* adjacent. */
if (w1->signum < w2->signum) return -1;
if (w1->signum > w2->signum) return 1;
/* Sort by loop pointer, so we can easily look up the first item after
* { .signum = x, .loop = NULL }. */
if ((uintptr_t) w1->loop < (uintptr_t) w2->loop) return -1;
if ((uintptr_t) w1->loop > (uintptr_t) w2->loop) return 1;
if ((uintptr_t) w1 < (uintptr_t) w2) return -1;
if ((uintptr_t) w1 > (uintptr_t) w2) return 1;
return 0;
}
RB_GENERATE_STATIC(uv_signal_tree_s, uv_signal_s, tree_entry, uv__signal_compare)
/*
* Dispatches signal {signum} to all active uv_signal_t watchers in all loops.
* Returns 1 if the signal was dispatched to any watcher, or 0 if there were
* no active signal watchers observing this signal.
*/
int uv__signal_dispatch(int signum) {
uv_signal_t lookup;
uv_signal_t* handle;
int dispatched;
dispatched = 0;
EnterCriticalSection(&uv__signal_lock);
lookup.signum = signum;
lookup.loop = NULL;
for (handle = RB_NFIND(uv_signal_tree_s, &uv__signal_tree, &lookup);
handle != NULL && handle->signum == signum;
handle = RB_NEXT(uv_signal_tree_s, &uv__signal_tree, handle)) {
unsigned long previous = InterlockedExchange(
(volatile LONG*) &handle->pending_signum, signum);
if (handle->flags & UV_SIGNAL_ONE_SHOT_DISPATCHED)
continue;
if (!previous) {
POST_COMPLETION_FOR_REQ(handle->loop, &handle->signal_req);
}
dispatched = 1;
if (handle->flags & UV_SIGNAL_ONE_SHOT)
handle->flags |= UV_SIGNAL_ONE_SHOT_DISPATCHED;
}
LeaveCriticalSection(&uv__signal_lock);
return dispatched;
}
static BOOL WINAPI uv__signal_control_handler(DWORD type) {
switch (type) {
case CTRL_C_EVENT:
return uv__signal_dispatch(SIGINT);
case CTRL_BREAK_EVENT:
return uv__signal_dispatch(SIGBREAK);
case CTRL_CLOSE_EVENT:
if (uv__signal_dispatch(SIGHUP)) {
/* Windows will terminate the process after the control handler
* returns. After that it will just terminate our process. Therefore
* block the signal handler so the main loop has some time to pick up
* the signal and do something for a few seconds. */
Sleep(INFINITE);
return TRUE;
}
return FALSE;
case CTRL_LOGOFF_EVENT:
case CTRL_SHUTDOWN_EVENT:
/* These signals are only sent to services. Services have their own
* notification mechanism, so there's no point in handling these. */
default:
/* We don't handle these. */
return FALSE;
}
}
int uv_signal_init(uv_loop_t* loop, uv_signal_t* handle) {
uv__handle_init(loop, (uv_handle_t*) handle, UV_SIGNAL);
handle->pending_signum = 0;
handle->signum = 0;
handle->signal_cb = NULL;
UV_REQ_INIT(&handle->signal_req, UV_SIGNAL_REQ);
handle->signal_req.data = handle;
return 0;
}
int uv_signal_stop(uv_signal_t* handle) {
uv_signal_t* removed_handle;
/* If the watcher wasn't started, this is a no-op. */
if (handle->signum == 0)
return 0;
EnterCriticalSection(&uv__signal_lock);
removed_handle = RB_REMOVE(uv_signal_tree_s, &uv__signal_tree, handle);
assert(removed_handle == handle);
LeaveCriticalSection(&uv__signal_lock);
handle->signum = 0;
uv__handle_stop(handle);
return 0;
}
int uv_signal_start(uv_signal_t* handle, uv_signal_cb signal_cb, int signum) {
return uv__signal_start(handle, signal_cb, signum, 0);
}
int uv_signal_start_oneshot(uv_signal_t* handle,
uv_signal_cb signal_cb,
int signum) {
return uv__signal_start(handle, signal_cb, signum, 1);
}
int uv__signal_start(uv_signal_t* handle,
uv_signal_cb signal_cb,
int signum,
int oneshot) {
/* Test for invalid signal values. */
if (signum <= 0 || signum >= NSIG)
return UV_EINVAL;
/* Short circuit: if the signal watcher is already watching {signum} don't go
* through the process of deregistering and registering the handler.
* Additionally, this avoids pending signals getting lost in the (small) time
* frame that handle->signum == 0. */
if (signum == handle->signum) {
handle->signal_cb = signal_cb;
return 0;
}
/* If the signal handler was already active, stop it first. */
if (handle->signum != 0) {
int r = uv_signal_stop(handle);
/* uv_signal_stop is infallible. */
assert(r == 0);
}
EnterCriticalSection(&uv__signal_lock);
handle->signum = signum;
if (oneshot)
handle->flags |= UV_SIGNAL_ONE_SHOT;
RB_INSERT(uv_signal_tree_s, &uv__signal_tree, handle);
LeaveCriticalSection(&uv__signal_lock);
handle->signal_cb = signal_cb;
uv__handle_start(handle);
return 0;
}
void uv_process_signal_req(uv_loop_t* loop, uv_signal_t* handle,
uv_req_t* req) {
long dispatched_signum;
assert(handle->type == UV_SIGNAL);
assert(req->type == UV_SIGNAL_REQ);
dispatched_signum = InterlockedExchange(
(volatile LONG*) &handle->pending_signum, 0);
assert(dispatched_signum != 0);
/* Check if the pending signal equals the signum that we are watching for.
* These can get out of sync when the handler is stopped and restarted while
* the signal_req is pending. */
if (dispatched_signum == handle->signum)
handle->signal_cb(handle, dispatched_signum);
if (handle->flags & UV_SIGNAL_ONE_SHOT)
uv_signal_stop(handle);
if (handle->flags & UV_HANDLE_CLOSING) {
/* When it is closing, it must be stopped at this point. */
assert(handle->signum == 0);
uv_want_endgame(loop, (uv_handle_t*) handle);
}
}
void uv_signal_close(uv_loop_t* loop, uv_signal_t* handle) {
uv_signal_stop(handle);
uv__handle_closing(handle);
if (handle->pending_signum == 0) {
uv_want_endgame(loop, (uv_handle_t*) handle);
}
}
void uv_signal_endgame(uv_loop_t* loop, uv_signal_t* handle) {
assert(handle->flags & UV_HANDLE_CLOSING);
assert(!(handle->flags & UV_HANDLE_CLOSED));
assert(handle->signum == 0);
assert(handle->pending_signum == 0);
handle->flags |= UV_HANDLE_CLOSED;
uv__handle_close(handle);
}