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 <[email protected]> --- 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
