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, 305 insertions, 0 deletions

diff --git a/tools/dumpimage.c b/tools/dumpimage.c
new file mode 100644
index 0000000..542ee28
--- /dev/null
+++ b/tools/dumpimage.c
@@ -0,0 +1,305 @@
+/*
+ * Based on mkimage.c.
+ *
+ * Written by Guilherme Maciel Ferreira <guilherme.maciel.ferreira@gmail.com>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#include "dumpimage.h"
+#include <image.h>
+#include <version.h>
+
+static void usage(void);
+
+/* image_type_params linked list to maintain registered image types supports */
+static struct image_type_params *dumpimage_tparams;
+
+/* parameters initialized by core will be used by the image type code */
+static struct image_tool_params params = {
+	.type = IH_TYPE_KERNEL,
+};
+
+/**
+ * dumpimage_register() - register respective image generation/list support
+ *
+ * the input struct image_type_params is checked and appended to the link
+ * list, if the input structure is already registered, issue an error
+ *
+ * @tparams: Image type parameters
+ */
+static void dumpimage_register(struct image_type_params *tparams)
+{
+	struct image_type_params **tp;
+
+	if (!tparams) {
+		fprintf(stderr, "%s: %s: Null input\n", params.cmdname,
+			__func__);
+		exit(EXIT_FAILURE);
+	}
+
+	/* scan the linked list, check for registry and point the last one */
+	for (tp = &dumpimage_tparams; *tp != NULL; tp = &(*tp)->next) {
+		if (!strcmp((*tp)->name, tparams->name)) {
+			fprintf(stderr, "%s: %s already registered\n",
+				params.cmdname, tparams->name);
+			return;
+		}
+	}
+
+	/* add input struct entry at the end of link list */
+	*tp = tparams;
+	/* mark input entry as last entry in the link list */
+	tparams->next = NULL;
+
+	debug("Registered %s\n", tparams->name);
+}
+
+/**
+ * dumpimage_get_type() - find the image type params for a given image type
+ *
+ * Scan all registered image types and check the input type_id for each
+ * supported image type
+ *
+ * @return respective image_type_params pointer. If the input type is not
+ * supported by any of registered image types, returns NULL
+ */
+static struct image_type_params *dumpimage_get_type(int type)
+{
+	struct image_type_params *curr;
+
+	for (curr = dumpimage_tparams; curr != NULL; curr = curr->next) {
+		if (curr->check_image_type) {
+			if (!curr->check_image_type(type))
+				return curr;
+		}
+	}
+	return NULL;
+}
+
+/*
+ * dumpimage_verify_print_header() - verifies the image header
+ *
+ * Scan registered image types and verify the image_header for each
+ * supported image type. If verification is successful, this prints
+ * the respective header.
+ *
+ * @return 0 on success, negative if input image format does not match with
+ * any of supported image types
+ */
+static int dumpimage_verify_print_header(void *ptr, struct stat *sbuf)
+{
+	int retval = -1;
+	struct image_type_params *curr;
+
+	for (curr = dumpimage_tparams; curr != NULL; curr = curr->next) {
+		if (curr->verify_header) {
+			retval = curr->verify_header((unsigned char *)ptr,
+						     sbuf->st_size, &params);
+			if (retval != 0)
+				continue;
+			/*
+			 * Print the image information  if verify is
+			 * successful
+			 */
+			if (curr->print_header) {
+				curr->print_header(ptr);
+			} else {
+				fprintf(stderr,
+					"%s: print_header undefined for %s\n",
+					params.cmdname, curr->name);
+			}
+			break;
+		}
+	}
+
+	return retval;
+}
+
+/*
+ * dumpimage_extract_datafile -
+ *
+ * It scans all registered image types,
+ * verifies image_header for each supported image type
+ * if verification is successful, it extracts the desired file,
+ * indexed by pflag, from the image
+ *
+ * returns negative if input image format does not match with any of
+ * supported image types
+ */
+static int dumpimage_extract_datafile(void *ptr, struct stat *sbuf)
+{
+	int retval = -1;
+	struct image_type_params *curr;
+
+	for (curr = dumpimage_tparams; curr != NULL; curr = curr->next) {
+		if (curr->verify_header) {
+			retval = curr->verify_header((unsigned char *)ptr,
+						     sbuf->st_size, &params);
+			if (retval != 0)
+				continue;
+			/*
+			 * Extract the file from the image
+			 * if verify is successful
+			 */
+			if (curr->extract_datafile) {
+				curr->extract_datafile(ptr, &params);
+			} else {
+				fprintf(stderr,
+					"%s: extract_datafile undefined for %s\n",
+					params.cmdname, curr->name);
+			break;
+			}
+		}
+	}
+
+	return retval;
+}
+
+int main(int argc, char **argv)
+{
+	int opt;
+	int ifd = -1;
+	struct stat sbuf;
+	char *ptr;
+	int retval = 0;
+	struct image_type_params *tparams = NULL;
+
+	/* Init all image generation/list support */
+	register_image_tool(dumpimage_register);
+
+	params.cmdname = *argv;
+
+	while ((opt = getopt(argc, argv, "li:o:p:V")) != -1) {
+		switch (opt) {
+		case 'l':
+			params.lflag = 1;
+			break;
+		case 'i':
+			params.imagefile = optarg;
+			params.iflag = 1;
+			break;
+		case 'o':
+			params.outfile = optarg;
+			break;
+		case 'p':
+			params.pflag = strtoul(optarg, &ptr, 10);
+			if (*ptr) {
+				fprintf(stderr,
+					"%s: invalid file position %s\n",
+					params.cmdname, *argv);
+				exit(EXIT_FAILURE);
+			}
+			break;
+		case 'V':
+			printf("dumpimage version %s\n", PLAIN_VERSION);
+			exit(EXIT_SUCCESS);
+		default:
+			usage();
+		}
+	}
+
+	if (optind >= argc)
+		usage();
+
+	/* set tparams as per input type_id */
+	tparams = dumpimage_get_type(params.type);
+	if (tparams == NULL) {
+		fprintf(stderr, "%s: unsupported type %s\n",
+			params.cmdname, genimg_get_type_name(params.type));
+		exit(EXIT_FAILURE);
+	}
+
+	/*
+	 * check the passed arguments parameters meets the requirements
+	 * as per image type to be generated/listed
+	 */
+	if (tparams->check_params) {
+		if (tparams->check_params(&params))
+			usage();
+	}
+
+	if (params.iflag)
+		params.datafile = argv[optind];
+	else
+		params.imagefile = argv[optind];
+	if (!params.outfile)
+		params.outfile = params.datafile;
+
+	ifd = open(params.imagefile, O_RDONLY|O_BINARY);
+	if (ifd < 0) {
+		fprintf(stderr, "%s: Can't open \"%s\": %s\n",
+			params.cmdname, params.imagefile,
+			strerror(errno));
+		exit(EXIT_FAILURE);
+	}
+
+	if (params.lflag || params.iflag) {
+		if (fstat(ifd, &sbuf) < 0) {
+			fprintf(stderr, "%s: Can't stat \"%s\": %s\n",
+				params.cmdname, params.imagefile,
+				strerror(errno));
+			exit(EXIT_FAILURE);
+		}
+
+		if ((unsigned)sbuf.st_size < tparams->header_size) {
+			fprintf(stderr,
+				"%s: Bad size: \"%s\" is not valid image\n",
+				params.cmdname, params.imagefile);
+			exit(EXIT_FAILURE);
+		}
+
+		ptr = mmap(0, sbuf.st_size, PROT_READ, MAP_SHARED, ifd, 0);
+		if (ptr == MAP_FAILED) {
+			fprintf(stderr, "%s: Can't read \"%s\": %s\n",
+				params.cmdname, params.imagefile,
+				strerror(errno));
+			exit(EXIT_FAILURE);
+		}
+
+		/*
+		 * Both calls bellow scan through dumpimage registry for all
+		 * supported image types and verify the input image file
+		 * header for match
+		 */
+		if (params.iflag) {
+			/*
+			 * Extract the data files from within the matched
+			 * image type. Returns the error code if not matched
+			 */
+			retval = dumpimage_extract_datafile(ptr, &sbuf);
+		} else {
+			/*
+			 * Print the image information for matched image type
+			 * Returns the error code if not matched
+			 */
+			retval = dumpimage_verify_print_header(ptr, &sbuf);
+		}
+
+		(void)munmap((void *)ptr, sbuf.st_size);
+		(void)close(ifd);
+
+		return retval;
+	}
+
+	(void)close(ifd);
+
+	return EXIT_SUCCESS;
+}
+
+static void usage(void)
+{
+	fprintf(stderr, "Usage: %s -l image\n"
+		"          -l ==> list image header information\n",
+		params.cmdname);
+	fprintf(stderr,
+		"       %s -i image [-p position] [-o outfile] data_file\n"
+		"          -i ==> extract from the 'image' a specific 'data_file'"
+		", indexed by 'position' (starting at 0)\n",
+		params.cmdname);
+	fprintf(stderr,
+		"       %s -V ==> print version information and exit\n",
+		params.cmdname);
+
+	exit(EXIT_FAILURE);
+}