Add support for signals using signalfd(2)

Signed-off-by: Joachim Nilsson <troglobit@gmail.com>

signal.c

@@ -0,0 +1,130 @@
+/* libuev - Micro event loop library
+ *
+ * Copyright (c) 2012  Flemming Madsen <flemming!madsen()madsensoft!dk>
+ * Copyright (c) 2013  Joachim Nilsson <troglobit()gmail!com>
+ *
+ * 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 <errno.h>
+#include <signal.h>
+#include <sys/signalfd.h>
+#include <unistd.h>		/* close(), read() */
+
+#include "uev.h"
+
+
+/**
+ * Create a signal watcher
+ * @param ctx     A valid libuev context
+ * @param handler Timer callback
+ * @param data    Optional callback argument
+ * @param signo   Signal to watch for
+ *
+ * @return The new watcher, or %NULL with @param errno set on error.
+ */
+uev_watcher_t *uev_signal_create(uev_t *ctx, uev_cb_t *handler, void *data, int signo)
+{
+	int fd;
+	sigset_t mask;
+	uev_watcher_t *w;
+
+	sigemptyset(&mask);
+	fd = signalfd(-1, &mask, SFD_NONBLOCK);
+	if (fd < 0)
+		return NULL;
+
+	w = uev_watcher_create(ctx, UEV_SIGNAL_TYPE, fd, UEV_DIR_INBOUND, handler, data);
+	if (!w)
+		goto exit;
+
+	if (uev_signal_set(ctx, w, signo)) {
+		uev_watcher_delete(ctx, w);
+	exit:
+		close(fd);
+		return NULL;
+	}
+
+	return w;
+}
+
+/**
+ * Reset a signal watcher
+ * @param ctx   A valid libuev context
+ * @param w     Watcher to reset
+ * @param signo New signal to watch for
+ *
+ * @return POSIX OK(0) or non-zero with @param errno set.
+ */
+int uev_signal_set(uev_t *ctx, uev_watcher_t *w, int signo)
+{
+	sigset_t mask;
+
+	if (!ctx || !w) {
+		errno = EINVAL;
+		return -1;
+	}
+
+	sigemptyset(&mask);
+	sigaddset(&mask, signo);
+
+	/* Block signals so that they aren't handled
+	   according to their default dispositions */
+
+	if (sigprocmask(SIG_BLOCK, &mask, NULL) == -1)
+		return -1;
+
+	if (signalfd(w->fd, &mask, SFD_NONBLOCK) < 0)
+		return -1;
+
+	return 0;
+}
+
+/**
+ * Delete a signal watcher
+ * @param ctx  A valid libuev context
+ * @param w    Watcher to delete
+ *
+ * @return POSIX OK(0) or non-zero with @param errno set.
+ */
+int uev_signal_delete(uev_t *ctx, uev_watcher_t *w)
+{
+	int fd;
+
+	if (!ctx || !w) {
+		errno = EINVAL;
+		return -1;
+	}
+
+	uev_timer_set(ctx, w, 0, 0);
+	fd = w->fd;
+	uev_watcher_delete(ctx, w);
+	close(fd);
+
+	return 0;
+}
+
+/**
+ * Local Variables:
+ *  version-control: t
+ *  indent-tabs-mode: t
+ *  c-file-style: "linux"
+ * End:
+ */