Add dumpimage, a tool to extract data from U-Boot images

Given a multi-file image created through the mkimage's -d option:

  $ mkimage -A x86 -O linux -T multi -n x86 -d vmlinuz:initrd.img:System.map \
  multi.img

  Image Name:   x86
  Created:      Thu Jul 25 10:29:13 2013
  Image Type:   Intel x86 Linux Multi-File Image (gzip compressed)
  Data Size:    13722956 Bytes = 13401.32 kB = 13.09 MB
  Load Address: 00000000
  Entry Point:  00000000
  Contents:
     Image 0: 4040128 Bytes = 3945.44 kB = 3.85 MB
     Image 1: 7991719 Bytes = 7804.41 kB = 7.62 MB
     Image 2: 1691092 Bytes = 1651.46 kB = 1.61 MB

It is possible to perform the innverse operation -- extracting any file from
the image -- by using the dumpimage's -i option:

  $ dumpimage -i multi.img -p 2 System.map

Although it's feasible to retrieve "data files" from image through scripting,
the requirement to embed tools such 'dd', 'awk' and 'sed' for this sole purpose
is cumbersome and unreliable -- once you must keep track of file sizes inside
the image. Furthermore, extracting data files using "dumpimage" tool is faster
than through scripting.

Signed-off-by: Guilherme Maciel Ferreira <guilherme.maciel.ferreira@gmail.com>
Signed-off-by: Simon Glass <sjg@chromium.org>

1 files changed, 57 insertions, 0 deletions

diff --git a/tools/default_image.c b/tools/default_image.c
index cc790b2..0a0792e 100644
--- a/tools/default_image.c
+++ b/tools/default_image.c
@@ -117,6 +117,62 @@ static void image_set_header(void *ptr, struct stat *sbuf, int ifd,
 	image_set_hcrc(hdr, checksum);
 }
 
+static int image_save_datafile(struct image_tool_params *params,
+			       ulong file_data, ulong file_len)
+{
+	int dfd;
+	const char *datafile = params->outfile;
+
+	dfd = open(datafile, O_RDWR | O_CREAT | O_TRUNC | O_BINARY,
+		   S_IRUSR | S_IWUSR);
+	if (dfd < 0) {
+		fprintf(stderr, "%s: Can't open \"%s\": %s\n",
+			params->cmdname, datafile, strerror(errno));
+		return -1;
+	}
+
+	if (write(dfd, (void *)file_data, file_len) != (ssize_t)file_len) {
+		fprintf(stderr, "%s: Write error on \"%s\": %s\n",
+			params->cmdname, datafile, strerror(errno));
+		close(dfd);
+		return -1;
+	}
+
+	close(dfd);
+
+	return 0;
+}
+
+static int image_extract_datafile(void *ptr, struct image_tool_params *params)
+{
+	const image_header_t *hdr = (const image_header_t *)ptr;
+	ulong file_data;
+	ulong file_len;
+
+	if (image_check_type(hdr, IH_TYPE_MULTI)) {
+		ulong idx = params->pflag;
+		ulong count;
+
+		/* get the number of data files present in the image */
+		count = image_multi_count(hdr);
+
+		/* retrieve the "data file" at the idx position */
+		image_multi_getimg(hdr, idx, &file_data, &file_len);
+
+		if ((file_len == 0) || (idx >= count)) {
+			fprintf(stderr, "%s: No such data file %ld in \"%s\"\n",
+				params->cmdname, idx, params->imagefile);
+			return -1;
+		}
+	} else {
+		file_data = image_get_data(hdr);
+		file_len = image_get_size(hdr);
+	}
+
+	/* save the "data file" into the file system */
+	return image_save_datafile(params, file_data, file_len);
+}
+
 /*
  * Default image type parameters definition
  */
@@ -128,6 +184,7 @@ static struct image_type_params defimage_params = {
 	.verify_header = image_verify_header,
 	.print_header = image_print_contents,
 	.set_header = image_set_header,
+	.extract_datafile = image_extract_datafile,
 	.check_params = image_check_params,
 };