libvirt/src/util-lib.c

/*
 * common, generic utility functions
 *
 * Copyright (C) 2006, 2007, 2008 Red Hat, Inc.
 * See COPYING.LIB for the License of this software
 */

#include <config.h>

#include <unistd.h>
#include <errno.h>

#include "util-lib.h"

/* Like read(), but restarts after EINTR */
int saferead(int fd, void *buf, size_t count)
{
	size_t nread = 0;
	while (count > 0) {
		ssize_t r = read(fd, buf, count);
		if (r < 0 && errno == EINTR)
			continue;
		if (r < 0)
			return r;
		if (r == 0)
			return nread;
		buf = (char *)buf + r;
		count -= r;
		nread += r;
	}
	return nread;
}

/* Like write(), but restarts after EINTR */
ssize_t safewrite(int fd, const void *buf, size_t count)
{
	size_t nwritten = 0;
	while (count > 0) {
		ssize_t r = write(fd, buf, count);

		if (r < 0 && errno == EINTR)
			continue;
		if (r < 0)
			return r;
		if (r == 0)
			return nwritten;
		buf = (const char *)buf + r;
		count -= r;
		nwritten += r;
	}
	return nwritten;
}