Add image.c and image.h. These files will contain functions to implement

the management of the raw image that's being created. The most notable of
the API is that there's no file descriptor argument. This is because the
image is managed in memory.

Once we have the in-memory (raw) image, we can write it out acording to
different formats. This two-pass approach shields schemes from formats
and formats from schemes.

Makefile

@@ -1,7 +1,7 @@
 # $FreeBSD$
 
 PROG=	mkimg
-SRCS=	mkimg.c scheme.c
+SRCS=	image.c mkimg.c scheme.c
 MAN=	mkimg.1
 
 CFLAGS+=-DSPARSE_WRITE

image.c

@@ -0,0 +1,92 @@
+/*-
+ * Copyright (c) 2014 Juniper Networks, Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+
+#include <sys/types.h>
+#include <assert.h>
+#include <errno.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+#include "mkimg.h"
+#include "image.h"
+
+#define	BUFFER_SIZE	(1024*1024)
+
+int
+image_copyin(lba_t blk, int fd, uint64_t *sizep)
+{
+	char *buffer;
+	uint64_t bytesize;
+	ssize_t bcnt, rdsz;
+	int error, partial;
+
+	assert(BUFFER_SIZE % secsz == 0);
+
+	buffer = malloc(BUFFER_SIZE);
+	if (buffer == NULL)
+		return (ENOMEM);
+	bytesize = 0;
+	partial = 0;
+	while (1) {
+		rdsz = read(fd, buffer, BUFFER_SIZE);
+		if (rdsz <= 0) {
+			error = (rdsz < 0) ? errno : 0;
+			break;
+		}
+		if (partial)
+			abort();
+		bytesize += rdsz;
+		bcnt = (rdsz + secsz - 1) / secsz;
+		error = image_write(blk, buffer, bcnt);
+		if (error)
+			break;
+		blk += bcnt;
+		partial = (bcnt * secsz != rdsz) ? 1 : 0;
+	}
+	free(buffer);
+	if (sizep != NULL)
+		*sizep = bytesize;
+	return (error);
+}
+
+int
+image_set_size(lba_t blk __unused)
+{
+
+	/* TODO */
+	return (0);
+}
+
+int
+image_write(lba_t blk __unused, void *buf __unused, ssize_t len __unused)
+{
+
+	/* TODO */
+	return (0);
+}

image.h

@@ -0,0 +1,36 @@
+/*-
+ * Copyright (c) 2014 Juniper Networks, Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ * $FreeBSD$
+ */
+
+#ifndef _MKIMG_IMAGE_H_
+#define	_MKIMG_IMAGE_H_
+
+int image_copyin(lba_t blk, int fd, uint64_t *sizep);
+int image_set_size(lba_t blk);
+int image_write(lba_t blk, void *buf, ssize_t len);
+
+#endif /* _MKIMG_IMAGE_H_ */