libsparse: add function to resparse a file and a utility to use it

Add sparse_file_repsarse, which splits chunks in an existing sparse
file such that the maximum size of a chunk, plus a header and footer,
is smaller than the given size.  This will allow multiple smaller
sparse files to result in the same data as a large sparse file.

Change-Id: I177abdb958a23d5afd394ff265c5b0c6a3ff22fa

1 files changed, 115 insertions, 0 deletions

diff --git a/libsparse/simg2simg.c b/libsparse/simg2simg.c
new file mode 100644
index 00000000..5f9ccf67
--- /dev/null
+++ b/libsparse/simg2simg.c
@@ -0,0 +1,115 @@
+/*
+ * Copyright (C) 2012 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#define _FILE_OFFSET_BITS 64
+#define _LARGEFILE64_SOURCE 1
+#define _GNU_SOURCE
+
+#include <fcntl.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+#include <sparse/sparse.h>
+
+#ifndef O_BINARY
+#define O_BINARY 0
+#endif
+
+void usage()
+{
+  fprintf(stderr, "Usage: simg2simg <sparse image file> <sparse_image_file> <max_size>\n");
+}
+
+int main(int argc, char *argv[])
+{
+	int in;
+	int out;
+	int i;
+	int ret;
+	struct sparse_file *s;
+	int64_t max_size;
+	struct sparse_file **out_s;
+	int files;
+	char filename[4096];
+
+	if (argc != 4) {
+		usage();
+		exit(-1);
+	}
+
+	max_size = atoll(argv[3]);
+
+	in = open(argv[1], O_RDONLY | O_BINARY);
+	if (in < 0) {
+		fprintf(stderr, "Cannot open input file %s\n", argv[1]);
+		exit(-1);
+	}
+
+	s = sparse_file_import(in, true, false);
+	if (!s) {
+		fprintf(stderr, "Failed to import sparse file\n");
+		exit(-1);
+	}
+
+	files = sparse_file_resparse(s, max_size, NULL, 0);
+	if (files < 0) {
+		fprintf(stderr, "Failed to resparse\n");
+		exit(-1);
+	}
+
+	out_s = calloc(sizeof(struct sparse_file *), files);
+	if (!out_s) {
+		fprintf(stderr, "Failed to allocate sparse file array\n");
+		exit(-1);
+	}
+
+	files = sparse_file_resparse(s, max_size, out_s, files);
+	if (files < 0) {
+		fprintf(stderr, "Failed to resparse\n");
+		exit(-1);
+	}
+
+	for (i = 0; i < files; i++) {
+		ret = snprintf(filename, sizeof(filename), "%s.%d", argv[2], i);
+		if (ret >= (int)sizeof(filename)) {
+			fprintf(stderr, "Filename too long\n");
+			exit(-1);
+		}
+
+		out = open(filename, O_WRONLY | O_CREAT | O_TRUNC | O_BINARY, 0664);
+		if (out < 0) {
+			fprintf(stderr, "Cannot open output file %s\n", argv[2]);
+			exit(-1);
+		}
+
+		ret = sparse_file_write(out_s[i], out, false, true, false);
+		if (ret) {
+			fprintf(stderr, "Failed to write sparse file\n");
+			exit(-1);
+		}
+		close(out);
+	}
+
+	close(in);
+
+	exit(0);
+}