Windows: Implement setitimer() and sigaction().
The timer is implemented using a thread that calls the signal handler at regular intervals. We also replace Windows's signal() function because we must intercept that SIGALRM is set (which is used when a timer is canceled). Signed-off-by: Johannes Sixt <johannes.sixt@telecom.at>
Johannes Sixt committed
Nov 13, 2007 at 10:14 UTC
6072fc314e87d53bec7266df5b6c3db2c2c82829
2 files changed
+113
-2
compat/mingw.c
+110
-2
@@ -125,12 +125,120 @@ struct passwd *getpwuid(int uid)
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return &p;
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}
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+static HANDLE timer_event;
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+static HANDLE timer_thread;
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+static int timer_interval;
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+static int one_shot;
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+static sig_handler_t timer_fn = SIG_DFL;
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+
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+/* The timer works like this:
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+ * The thread, ticktack(), is a trivial routine that most of the time
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+ * only waits to receive the signal to terminate. The main thread tells
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+ * the thread to terminate by setting the timer_event to the signalled
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+ * state.
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+ * But ticktack() interrupts the wait state after the timer's interval
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+ * length to call the signal handler.
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+ */
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+
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+static __stdcall unsigned ticktack(void *dummy)
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+{
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+ while (WaitForSingleObject(timer_event, timer_interval) == WAIT_TIMEOUT) {
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+ if (timer_fn == SIG_DFL)
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+ die("Alarm");
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+ if (timer_fn != SIG_IGN)
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+ timer_fn(SIGALRM);
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+ if (one_shot)
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+ break;
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+ }
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+ return 0;
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+}
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+
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+static int start_timer_thread(void)
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+{
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+ timer_event = CreateEvent(NULL, FALSE, FALSE, NULL);
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+ if (timer_event) {
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+ timer_thread = (HANDLE) _beginthreadex(NULL, 0, ticktack, NULL, 0, NULL);
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+ if (!timer_thread )
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+ return errno = ENOMEM,
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+ error("cannot start timer thread");
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+ } else
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+ return errno = ENOMEM,
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+ error("cannot allocate resources for timer");
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+ return 0;
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+}
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+
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+static void stop_timer_thread(void)
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+{
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+ if (timer_event)
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+ SetEvent(timer_event); /* tell thread to terminate */
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+ if (timer_thread) {
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+ int rc = WaitForSingleObject(timer_thread, 1000);
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+ if (rc == WAIT_TIMEOUT)
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+ error("timer thread did not terminate timely");
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+ else if (rc != WAIT_OBJECT_0)
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+ error("waiting for timer thread failed: %lu",
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+ GetLastError());
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+ CloseHandle(timer_thread);
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+ }
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+ if (timer_event)
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+ CloseHandle(timer_event);
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+ timer_event = NULL;
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+ timer_thread = NULL;
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+}
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+
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+static inline int is_timeval_eq(const struct timeval *i1, const struct timeval *i2)
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+{
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+ return i1->tv_sec == i2->tv_sec && i1->tv_usec == i2->tv_usec;
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+}
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+
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int setitimer(int type, struct itimerval *in, struct itimerval *out)
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{
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- return -1;
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+ static const struct timeval zero;
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+ static int atexit_done;
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+
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+ if (out != NULL)
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+ return errno = EINVAL,
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+ error("setitimer param 3 != NULL not implemented");
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+ if (!is_timeval_eq(&in->it_interval, &zero) &&
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+ !is_timeval_eq(&in->it_interval, &in->it_value))
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+ return errno = EINVAL,
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+ error("setitimer: it_interval must be zero or eq it_value");
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+
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+ if (timer_thread)
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+ stop_timer_thread();
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+
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+ if (is_timeval_eq(&in->it_value, &zero) &&
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+ is_timeval_eq(&in->it_interval, &zero))
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+ return 0;
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+
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+ timer_interval = in->it_value.tv_sec * 1000 + in->it_value.tv_usec / 1000;
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+ one_shot = is_timeval_eq(&in->it_interval, &zero);
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+ if (!atexit_done) {
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+ atexit(stop_timer_thread);
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+ atexit_done = 1;
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+ }
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+ return start_timer_thread();
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}
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int sigaction(int sig, struct sigaction *in, struct sigaction *out)
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{
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- return -1;
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+ if (sig != SIGALRM)
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+ return errno = EINVAL,
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+ error("sigaction only implemented for SIGALRM");
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+ if (out != NULL)
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+ return errno = EINVAL,
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+ error("sigaction: param 3 != NULL not implemented");
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+
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+ timer_fn = in->sa_handler;
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+ return 0;
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+}
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+
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+#undef signal
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+sig_handler_t mingw_signal(int sig, sig_handler_t handler)
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+{
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+ if (sig != SIGALRM)
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+ return signal(sig, handler);
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+ sig_handler_t old = timer_fn;
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+ timer_fn = handler;
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+ return old;
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}
compat/mingw.h
+3
@@ -154,6 +154,9 @@ char *mingw_getcwd(char *pointer, int len);
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int mingw_rename(const char*, const char*);
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#define rename mingw_rename
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+sig_handler_t mingw_signal(int sig, sig_handler_t handler);
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+#define signal mingw_signal
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+
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/*
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* git specific compatibility
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*/