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>

Makefile

@@ -797,6 +797,7 @@ clean:
 	       $(obj)tools/envcrc					  \
 	       $(obj)tools/gdb/{astest,gdbcont,gdbsend}			  \
 	       $(obj)tools/gen_eth_addr    $(obj)tools/img2srec		  \
+	       $(obj)tools/dump{env,}image		  \
 	       $(obj)tools/mk{env,}image   $(obj)tools/mpc86x_clk	  \
 	       $(obj)tools/mk{$(BOARD),}spl				  \
 	       $(obj)tools/mxsboot					  \

README

@@ -5252,6 +5252,15 @@ when your kernel is intended to use an initial ramdisk:
 	Load Address: 0x00000000
 	Entry Point:  0x00000000
 
+The "dumpimage" is a tool to disassemble images built by mkimage. Its "-i"
+option performs the converse operation of the mkimage's second form (the "-d"
+option). Given an image built by mkimage, the dumpimage extracts a "data file"
+from the image:
+
+	tools/dumpimage -i image -p position data_file
+	  -i ==> extract from the 'image' a specific 'data_file', \
+	   indexed by 'position'
+
 
 Installing a Linux Image:
 -------------------------

tools/.gitignore

@@ -3,6 +3,7 @@
 /gen_eth_addr
 /img2srec
 /kwboot
+/dumpimage
 /mkenvimage
 /mkimage
 /mpc86x_clk

tools/Makefile

@@ -50,6 +50,7 @@ BIN_FILES-$(CONFIG_BUILD_ENVCRC) += envcrc$(SFX)
 BIN_FILES-$(CONFIG_CMD_NET) += gen_eth_addr$(SFX)
 BIN_FILES-$(CONFIG_CMD_LOADS) += img2srec$(SFX)
 BIN_FILES-$(CONFIG_XWAY_SWAP_BYTES) += xway-swap-bytes$(SFX)
+BIN_FILES-y += dumpimage$(SFX)
 BIN_FILES-y += mkenvimage$(SFX)
 BIN_FILES-y += mkimage$(SFX)
 BIN_FILES-$(CONFIG_EXYNOS5250) += mk$(BOARD)spl$(SFX)
@@ -72,6 +73,7 @@ EXT_OBJ_FILES-y += lib/sha1.o
 # Source files located in the tools directory
 NOPED_OBJ_FILES-y += aisimage.o
 NOPED_OBJ_FILES-y += default_image.o
+NOPED_OBJ_FILES-y += dumpimage.o
 NOPED_OBJ_FILES-y += fit_image.o
 NOPED_OBJ_FILES-y += image-host.o
 NOPED_OBJ_FILES-y += imximage.o
@@ -200,6 +202,30 @@ $(obj)xway-swap-bytes$(SFX):	$(obj)xway-swap-bytes.o
 	$(HOSTCC) $(HOSTCFLAGS) $(HOSTLDFLAGS) -o $@ $^
 	$(HOSTSTRIP) $@
 
+$(obj)dumpimage$(SFX):	$(obj)aisimage.o \
+			$(FIT_SIG_OBJS) \
+			$(obj)crc32.o \
+			$(obj)default_image.o \
+			$(obj)fit_image.o \
+			$(obj)image-fit.o \
+			$(obj)image.o \
+			$(obj)image-host.o \
+			$(obj)imagetool.o \
+			$(obj)imximage.o \
+			$(obj)kwbimage.o \
+			$(obj)dumpimage.o \
+			$(obj)md5.o \
+			$(obj)mxsimage.o \
+			$(obj)omapimage.o \
+			$(obj)os_support.o \
+			$(obj)pblimage.o \
+			$(obj)sha1.o \
+			$(obj)ublimage.o \
+			$(LIBFDT_OBJS) \
+			$(RSA_OBJS)
+	$(HOSTCC) $(HOSTCFLAGS) $(HOSTLDFLAGS) -o $@ $^ $(HOSTLIBS)
+	$(HOSTSTRIP) $@
+
 $(obj)mkenvimage$(SFX):	$(obj)crc32.o $(obj)mkenvimage.o \
 	$(obj)os_support.o
 	$(HOSTCC) $(HOSTCFLAGS) $(HOSTLDFLAGS) -o $@ $^

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,
 };
 

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);
+}

tools/dumpimage.h

@@ -0,0 +1,33 @@
+/*
+ * Based on mkimage.c.
+ *
+ * Written by Guilherme Maciel Ferreira <guilherme.maciel.ferreira@gmail.com>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#ifndef _DUMPIMAGE_H_
+#define _DUMPIMAGE_H_
+
+#include "os_support.h"
+#include <errno.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/stat.h>
+#include <time.h>
+#include <unistd.h>
+#include <sha1.h>
+#include "fdt_host.h"
+#include "imagetool.h"
+
+#undef DUMPIMAGE_DEBUG
+
+#ifdef DUMPIMAGE_DEBUG
+#define debug(fmt, args...)	printf(fmt, ##args)
+#else
+#define debug(fmt, args...)
+#endif /* DUMPIMAGE_DEBUG */
+
+#endif /* _DUMPIMAGE_H_ */

tools/imagetool.h

@@ -34,7 +34,9 @@ struct image_tool_params {
 	int dflag;
 	int eflag;
 	int fflag;
+	int iflag;
 	int lflag;
+	int pflag;
 	int vflag;
 	int xflag;
 	int skipcpy;
@@ -50,6 +52,7 @@ struct image_tool_params {
 	char *datafile;
 	char *imagefile;
 	char *cmdname;
+	const char *outfile;	/* Output filename */
 	const char *keydir;	/* Directory holding private keys */
 	const char *keydest;	/* Destination .dtb for public key */
 	const char *comment;	/* Comment to add to signature node */
@@ -96,6 +99,15 @@ struct image_type_params {
 	 */
 	void (*set_header) (void *, struct stat *, int,
 					struct image_tool_params *);
+	/*
+	 * This function is used by the command to retrieve a data file from
+	 * the image (i.e. dumpimage -i <image> -p <position> <data_file>).
+	 * Thus the code to extract a file from an image must be put here.
+	 *
+	 * Returns 0 if the file was successfully retrieved from the image,
+	 * or a negative value on error.
+	 */
+	int (*extract_datafile) (void *, struct image_tool_params *);
 	/*
 	 * Some image generation support for ex (default image type) supports
 	 * more than one type_ids, this callback function is used to check