From d50c437a65028f95aa72162004f2b61f64131a50 Mon Sep 17 00:00:00 2001
From: Simon Rettberg
Date: Wed, 10 Feb 2016 14:26:54 +0100
Subject: [SHARED] signal.h -> fdsignal.h

---
 src/shared/fdsignal.inc/pipe64.c | 88 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 88 insertions(+)
 create mode 100644 src/shared/fdsignal.inc/pipe64.c

(limited to 'src/shared/fdsignal.inc/pipe64.c')

diff --git a/src/shared/fdsignal.inc/pipe64.c b/src/shared/fdsignal.inc/pipe64.c
new file mode 100644
index 0000000..4f0614b
--- /dev/null
+++ b/src/shared/fdsignal.inc/pipe64.c
@@ -0,0 +1,88 @@
+#include <poll.h>
+#include <inttypes.h>
+#include <errno.h>
+#include <unistd.h>
+#include <fcntl.h>
+
+#define P_READ (0)
+#define P_WRITE (1)
+
+/*
+ * Generic (posix) implelentation of signals, using pipes.
+ * 64bit version, packing two ints into a pointer.
+ * This version requires that you use -fno-strict-aliasing
+ * since it's doing evil pointer casting.
+ */
+
+dnbd3_signal_t* signal_new()
+{
+	int fds[2];
+	if ( pipe( fds ) == -1 ) return NULL;
+	fcntl( fds[P_READ], F_SETFL, O_NONBLOCK );
+	fcntl( fds[P_WRITE], F_SETFL, O_NONBLOCK );
+	return (dnbd3_signal_t*)*((uintptr_t*)fds);
+}
+
+dnbd3_signal_t* signal_newBlocking()
+{
+	int fds[2];
+	if ( pipe( fds ) == -1 ) return NULL;
+	return (dnbd3_signal_t*)*((uintptr_t*)fds);
+}
+
+int signal_call(const dnbd3_signal_t* const signal)
+{
+	if ( signal == NULL ) return SIGNAL_ERROR;
+	static char one = 1;
+	const int* fds = (int*)&signal;
+	// Write one byte on every call, so the number of bytes read will
+	// match the number of events
+	return write( fds[P_WRITE], &one, 1 ) > 0 ? SIGNAL_OK : SIGNAL_ERROR;
+}
+
+int signal_wait(const dnbd3_signal_t* const signal, int timeoutMs)
+{
+	if ( signal == NULL ) return SIGNAL_ERROR;
+	const int* fds = (int*)&signal;
+	struct pollfd ps = {
+		.fd = fds[P_READ],
+		.events = POLLIN
+	};
+	int ret = poll( &ps, 1, timeoutMs );
+	if ( ret == 0 ) return SIGNAL_TIMEOUT;
+	if ( ret == -1 ) return SIGNAL_ERROR;
+	if ( ps.revents & ( POLLERR | POLLNVAL ) ) return SIGNAL_ERROR;
+	return signal_clear( signal );
+}
+
+int signal_clear(const dnbd3_signal_t* const signal)
+{
+	if ( signal == NULL ) return SIGNAL_ERROR;
+	char throwaway[100];
+	const int* fds = (int*)&signal;
+	ssize_t ret, total = 0;
+	do {
+		ret = read( fds[P_READ], throwaway, sizeof throwaway );
+		if ( ret < 0 ) {
+			if ( errno == EAGAIN ) return total;
+			return SIGNAL_ERROR;
+		}
+		total += ret;
+	} while ( (size_t)ret == sizeof throwaway );
+	return (int)total;
+}
+
+void signal_close(const dnbd3_signal_t* const signal)
+{
+	const int* fds = (int*)&signal;
+	close( fds[P_READ] );
+	close( fds[P_WRITE] );
+}
+
+int signal_getWaitFd(const dnbd3_signal_t* const signal)
+{
+	if ( signal == NULL ) return -1;
+	const int* fds = (int*)&signal;
+	return fds[P_READ];
+}
+
-- 
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