[powerdebug,01/17] add a real mainloop

diff --git a/Makefile b/Makefile
index 1a53121..8d41b24 100644
--- a/Makefile
+++ b/Makefile
@@ -4,7 +4,8 @@  MANDIR=/usr/share/man/man8
 CFLAGS?=-O1 -g -Wall -Wshadow
 CC?=gcc
 
-OBJS = powerdebug.o sensor.o clocks.o regulator.o display.o tree.o utils.o
+OBJS = powerdebug.o sensor.o clocks.o regulator.o \
+	display.o tree.o utils.o mainloop.o
 
 default: powerdebug
 
diff --git a/mainloop.c b/mainloop.c
new file mode 100644
index 0000000..d63d703
--- /dev/null
+++ b/mainloop.c
@@ -0,0 +1,122 @@ 
+/*******************************************************************************
+ * Copyright (C) 2010, Linaro Limited.
+ *
+ * This file is part of PowerDebug.
+ *
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License v1.0
+ * which accompanies this distribution, and is available at
+ * http://www.eclipse.org/legal/epl-v10.html
+ *
+ * Author:
+ *     Daniel Lezcano <daniel.lezcano@linaro.org>
+ *
+ *******************************************************************************/
+
+#include <stdlib.h>
+#include <errno.h>
+#include <unistd.h>
+#include <sys/epoll.h>
+#include "mainloop.h"
+
+static int epfd = -1;
+static unsigned short nrhandler;
+
+struct mainloop_data {
+	mainloop_callback_t cb;
+	void *data;
+	int fd;
+};
+
+struct mainloop_data **mds;
+
+#define MAX_EVENTS 10
+
+int _mainloop(unsigned int timeout)
+{
+        int i, nfds;
+        struct epoll_event events[MAX_EVENTS];
+	struct mainloop_data *md;
+
+	if (epfd < 0)
+		return -1;
+
+	for (;;) {
+
+                nfds = epoll_wait(epfd, events, MAX_EVENTS, timeout);
+                if (nfds < 0) {
+                        if (errno == EINTR)
+                                continue;
+                        return -1;
+                }
+
+                for (i = 0; i < nfds; i++) {
+			md = events[i].data.ptr;
+
+			if (md->cb(md->fd, md->data) > 0)
+				return 0;
+		}
+
+	}
+}
+
+int mainloop_add(int fd, mainloop_callback_t cb, void *data)
+{
+	struct epoll_event ev = {
+		.events = EPOLLIN,
+	};
+
+	struct mainloop_data *md;
+
+	if (fd >= nrhandler) {
+		mds = realloc(mds, sizeof(*mds) * (fd + 1));
+		if (!mds)
+			return -1;
+		nrhandler = fd + 1;
+	}
+
+	md = malloc(sizeof(*md));
+	if (!md)
+		return -1;
+
+	md->data = data;
+	md->cb = cb;
+	md->fd = fd;
+
+	mds[fd] = md;
+	ev.data.ptr = md;
+
+        if (epoll_ctl(epfd, EPOLL_CTL_ADD, fd, &ev) < 0) {
+		free(md);
+		return -1;
+	}
+
+	return 0;
+}
+
+int mainloop_del(int fd)
+{
+	if (fd >= nrhandler)
+		return -1;
+
+        if (epoll_ctl(epfd, EPOLL_CTL_DEL, fd, NULL) < 0)
+		return -1;
+
+	free(mds[fd]);
+
+	return 0;
+}
+
+int mainloop_init(void)
+{
+        epfd = epoll_create(2);
+        if (epfd < 0)
+                return -1;
+
+        return 0;
+}
+
+void mainloop_fini(void)
+{
+	close(epfd);
+}
diff --git a/mainloop.h b/mainloop.h
new file mode 100644
index 0000000..3b4c253
--- /dev/null
+++ b/mainloop.h
@@ -0,0 +1,22 @@ 
+/*******************************************************************************
+ * Copyright (C) 2010, Linaro Limited.
+ *
+ * This file is part of PowerDebug.
+ *
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License v1.0
+ * which accompanies this distribution, and is available at
+ * http://www.eclipse.org/legal/epl-v10.html
+ *
+ * Author:
+ *     Daniel Lezcano <daniel.lezcano@linaro.org>
+ *
+ *******************************************************************************/
+
+typedef int (*mainloop_callback_t)(int fd, void *data);
+
+extern int _mainloop(unsigned int timeout);
+extern int mainloop_add(int fd, mainloop_callback_t cb, void *data);
+extern int mainloop_del(int fd);
+extern int mainloop_init(void);
+extern void mainloop_fini(void);