An Android sparse image file generated by the 'genimage' tool can be seen as a
kind of compression, since it contains only the data which should really be
written to a device.
This implementation writes only the intended content and skips anything else.
Signed-off-by: Juergen Borleis <jbe@xxxxxxxxxxxxxx>
---
lib/uncompress.c | 82 +++++++++++++++++++++++++++++++++++++++++++++---
1 file changed, 78 insertions(+), 4 deletions(-)
diff --git a/lib/uncompress.c b/lib/uncompress.c
index 0608e9f..f17e9ce 100644
--- a/lib/uncompress.c
+++ b/lib/uncompress.c
@@ -25,6 +25,10 @@
#include <malloc.h>
#include <fs.h>
#include <libfile.h>
+#ifdef CONFIG_IMAGE_SPARSE
+#include <image-sparse.h>
+#include <linux/sizes.h>
+#endif
static void *uncompress_buf;
static unsigned int uncompress_size;
@@ -60,6 +64,71 @@ static int uncompress_fill(void *buf, unsigned int len)
return total;
}
+#ifdef CONFIG_IMAGE_SPARSE
+static int uncompress_sparse(int source, int destination)
+{
+ int ret = 0;
+ struct sparse_image_ctx *sparse;
+
+ /* rewind after checking the file type */
+ lseek(source, 0, SEEK_SET);
+
+ sparse = sparse_image_fd(source);
+ if (IS_ERR(sparse)) {
+ pr_err("Failed to open or interpret sparse image file: %m\n");
+ ret = 1;
+ goto on_error_dev;
+ }
+
+ const size_t transfer_buffer_length = SZ_128K;
+ unsigned char *buf = malloc(transfer_buffer_length);
+ if (!buf) {
+ pr_err("Failed to alloc memory for the transfers\n");
+ ret = 1;
+ goto on_error_sparse;
+ }
+
+ while (1) {
+ loff_t write_offset;
+ size_t write_length;
+
+ int rc = sparse_image_read(sparse, buf, &write_offset, transfer_buffer_length, &write_length);
+ if (rc) {
+ ret = 1;
+ goto on_error_memory;
+ }
+ if (!write_length)
+ break;
+
+ discard_range(destination, write_length, write_offset);
+
+ write_offset = lseek(destination, write_offset, SEEK_SET);
+ if (write_offset == -1) {
+ pr_err("Failed to set next data's destination offset: %m\n");
+ ret = 1;
+ goto on_error_memory;
+
+ }
+
+ rc = write_full(destination, buf, write_length);
+ if (rc < 0) {
+ pr_err("Failed to write destination's next data: %m\n");
+ ret = 1;
+ goto on_error_memory;
+ }
+ }
+
+on_error_memory:
+ free(buf);
+on_error_sparse:
+ free(sparse); /* Note: sparse_image_close(sparse); would also close the input file descriptor */
+on_error_dev:
+ return ret;
+}
+#endif
+
+static int uncompress_infd, uncompress_outfd;
+
int uncompress(unsigned char *inbuf, int len,
int(*fill)(void*, unsigned int),
int(*flush)(void*, unsigned int),
@@ -121,6 +190,10 @@ int uncompress(unsigned char *inbuf, int len,
case filetype_xz_compressed:
compfn = decompress_unxz;
break;
+#endif
+#ifdef CONFIG_IMAGE_SPARSE
+ case filetype_android_sparse:
+ break;
#endif
default:
err = basprintf("cannot handle filetype %s",
@@ -131,16 +204,17 @@ int uncompress(unsigned char *inbuf, int len,
goto err;
}
- ret = compfn(inbuf, len, fill ? uncompress_fill : NULL,
- flush, output, pos, error_fn);
+ if (ft == filetype_android_sparse)
+ ret = uncompress_sparse(uncompress_infd, uncompress_outfd);
+ else
+ ret = compfn(inbuf, len, fill ? uncompress_fill : NULL,
+ flush, output, pos, error_fn);
err:
free(uncompress_buf);
return ret;
}
-static int uncompress_infd, uncompress_outfd;
-
static int fill_fd(void *buf, unsigned int len)
{
return read_full(uncompress_infd, buf, len);
--
2.30.2
