cbfs: fix issues with word size and endianness.

Add XDR functions and use them to convert the ELF headers
to native headers, using the Elf64 structs to ensure we accomodate
all word sizes. Also, use these XDR functions for output.

This may seem overly complex but it turned out to be much the easiest
way to do this. Note that the basic elf parsing function
in cbfs-mkstage.c now works over all ELF files, for all architectures,
endian, and word size combinations. At the same time, the basic elf
parsing in cbfs-mkstage.c is a loop that has no architecture-specific
conditionals.

Add -g to the LDFLAGS while we're here. It's on the CFLAGS so there is
no harm done.

This code has been tested on all chromebooks that use coreboot to date.

I added most of the extra checks from ChromeOS and they triggered a
lot of warnings, hence the other changes. I had to take -Wshadow back
out due to the many errors it triggers in LZMA.

BUG=None
TEST=Build and boot for Peppy; works fine. Build and boot for nyan,
     works fine. Build for qemu targets and armv8 targets.
BRANCH=None

Change-Id: I5a4cee9854799189115ac701e22efc406a8d902f
Signed-off-by: Ronald G. Minnich <rminnich@google.com>
Reviewed-on: https://chromium-review.googlesource.com/178606
Reviewed-by: Ronald Minnich <rminnich@chromium.org>
Commit-Queue: Ronald Minnich <rminnich@chromium.org>
Tested-by: Ronald Minnich <rminnich@chromium.org>
Reviewed-on: http://review.coreboot.org/4817
Reviewed-by: Alexandru Gagniuc <mr.nuke.me@gmail.com>
Tested-by: build bot (Jenkins)
Reviewed-by: Ronald G. Minnich <rminnich@gmail.com>

9 files changed, 505 insertions, 116 deletions

diff --git a/util/cbfstool/Makefile b/util/cbfstool/Makefile
index 3aa5edc718..5e4fdcbd7b 100644
--- a/util/cbfstool/Makefile
+++ b/util/cbfstool/Makefile
@@ -1,13 +1,19 @@
 obj ?= $(shell pwd)
 
-HOSTCC   ?= gcc
-CFLAGS   ?= -g -Wall -Werror
-CFLAGS   += -D_7ZIP_ST
+HOSTCC ?= gcc
+CFLAGS ?= -g
+CFLAGS += -D_7ZIP_ST
+CFLAGS += -Wall -Wundef -Wstrict-prototypes -Wmissing-prototypes
+CFLAGS += -Wwrite-strings -Wredundant-decls -Wno-trigraphs
+CFLAGS += -Wstrict-aliasing -Werror
+# You're going to have to fix the LzmaEnc.c first -- it's horrible.
+# CFLAGS += -Wshadow
+LDFLAGS += -g
 
 BINARY:=$(obj)/cbfstool
 
 COMMON:=cbfstool.o common.o cbfs_image.o compress.o fit.o
-COMMON+=cbfs-mkstage.o cbfs-mkpayload.o
+COMMON+=cbfs-mkstage.o cbfs-mkpayload.o xdr.o
 # LZMA
 COMMON+=lzma/lzma.o
 COMMON+=lzma/C/LzFind.o  lzma/C/LzmaDec.o  lzma/C/LzmaEnc.o
diff --git a/util/cbfstool/Makefile.inc b/util/cbfstool/Makefile.inc
index fc120f3b22..4270d750cc 100644
--- a/util/cbfstool/Makefile.inc
+++ b/util/cbfstool/Makefile.inc
@@ -5,6 +5,7 @@ cbfsobj += compress.o
 cbfsobj += cbfs_image.o
 cbfsobj += cbfs-mkstage.o
 cbfsobj += cbfs-mkpayload.o
+cbfsobj += xdr.o
 cbfsobj += fit.o
 # LZMA
 cbfsobj += lzma.o
diff --git a/util/cbfstool/cbfs-mkstage.c b/util/cbfstool/cbfs-mkstage.c
index dfc93c20e9..5c8014f072 100644
--- a/util/cbfstool/cbfs-mkstage.c
+++ b/util/cbfstool/cbfs-mkstage.c
@@ -28,46 +28,204 @@
 #include "cbfs.h"
 #include "elf.h"
 
-static unsigned int idemp(unsigned int x)
-{
-	return x;
-}
+/*
+ * Short form: this is complicated, but we've tried making it simple
+ * and we keep hitting problems with our ELF parsing.
+ *
+ * The ELF parsing situation has always been a bit tricky.  In fact,
+ * we (and most others) have been getting it wrong in small ways for
+ * years. Recently this has caused real trouble for the ARM V8 build.
+ * In this file we attempt to finally get it right for all variations
+ * of endian-ness and word size and target architectures and
+ * architectures we might get run on. Phew!. To do this we borrow a
+ * page from the FreeBSD NFS xdr model (see elf_ehdr and elf_phdr),
+ * the Plan 9 endianness functions (see xdr.c), and Go interfaces (see
+ * how we use buffer structs in this file). This ends up being a bit
+ * wordy at the lowest level, but greatly simplifies the elf parsing
+ * code and removes a common source of bugs, namely, forgetting to
+ * flip type endianness when referencing a struct member.
+ *
+ * ELF files can have four combinations of data layout: 32/64, and
+ * big/little endian.  Further, to add to the fun, depending on the
+ * word size, the size of the ELF structs varies. The coreboot SELF
+ * format is simpler in theory: it's supposed to be always BE, and the
+ * various struct members allow room for growth: the entry point is
+ * always 64 bits, for example, so the size of a SELF struct is
+ * constant, regardless of target architecture word size.  Hence, we
+ * need to do some transformation of the ELF files.
+ *
+ * A given architecture, realistically, only supports one of the four
+ * combinations at a time as the 'native' format. Hence, our code has
+ * been sprinkled with every variation of [nh]to[hn][sll] over the
+ * years. We've never quite gotten it all right, however, and a quick
+ * pass over this code revealed another bug.  It's all worked because,
+ * until now, all the working platforms that had CBFS were 32 LE. Even then,
+ * however, bugs crept in: we recently realized that we're not
+ * transforming the entry point to big format when we store into the
+ * SELF image.
+ *
+ * The problem is essentially an XDR operation:
+ * we have something in a foreign format and need to transform it.
+ * It's most like XDR because:
+ * 1) the byte order can be wrong
+ * 2) the word size can be wrong
+ * 3) the size of elements in the stream depends on the value
+ *    of other elements in the stream
+ * it's not like XDR because:
+ * 1) the byte order can be right
+ * 2) the word size can be right
+ * 3) the struct members are all on a natural alignment
+ *
+ * Hence, this new approach.  To cover word size issues, we *always*
+ * transform the two structs we care about, the file header and
+ * program header, into a native struct in the 64 bit format:
+ *
+ * [32,little] -> [Elf64_Ehdr, Elf64_Phdr]
+ * [64,little] -> [Elf64_Ehdr, Elf64_Phdr]
+ * [32,big] -> [Elf64_Ehdr, Elf64_Phdr]
+ * [64,big] -> [Elf64_Ehdr, Elf64_Phdr]
+ * Then we just use those structs, and all the need for inline ntoh* goes away,
+ * as well as all the chances for error.
+ * This works because all the SELF structs have fields large enough for
+ * the largest ELF 64 struct members, and all the Elf64 struct members
+ * are at least large enough for all ELF 32 struct members.
+ * We end up with one function to do all our ELF parsing, and two functions
+ * to transform the headers. For the put case, we also have
+ * XDR functions, and hopefully we'll never again spend 5 years with the
+ * wrong endian-ness on an output value :-)
+ * This should work for all word sizes and endianness we hope to target.
+ * I *really* don't want to be here for 128 bit addresses.
+ *
+ * The parse functions are called with a pointer to an input buffer
+ * struct. One might ask: are there enough bytes in the input buffer?
+ * We know there need to be at *least* sizeof(Elf32_Ehdr) +
+ * sizeof(Elf32_Phdr) bytes. Realistically, there has to be some data
+ * too.  If we start to worry, though we have not in the past, we
+ * might apply the simple test: the input buffer needs to be at least
+ * sizeof(Elf64_Ehdr) + sizeof(Elf64_Phdr) bytes because, even if it's
+ * ELF 32, there's got to be *some* data! This is not theoretically
+ * accurate but it is actually good enough in practice. It allows the
+ * header transformation code to ignore the possibility of underrun.
+ *
+ * We also must accomodate different ELF files, and hence formats,
+ * in the same cbfs invocation. We might load a 64-bit payload
+ * on a 32-bit machine; we might even have a mixed armv7/armv8
+ * SOC or even a system with an x86/ARM!
+ *
+ * A possibly problematic (though unlikely to be so) assumption
+ * is that we expect the BIOS to remain in the lowest 32 bits
+ * of the physical address space. Since ARMV8 has standardized
+ * on that, and x86_64 also has, this seems a safe assumption.
+ *
+ * To repeat, ELF structs are different sizes because ELF struct
+ * members are different sizes, depending on values in the ELF file
+ * header. For this we use the functions defined in xdr.c, which
+ * consume bytes, convert the endianness, and advance the data pointer
+ * in the buffer struct.
+ */
 
-/* This is a wrapper around the swab32() macro to make it
- * usable for the current implementation of parse_elf_to_stage()
+/* Get the ident array, so we can figure out
+ * endian-ness, word size, and in future other useful
+ * parameters
  */
-static unsigned int swap32(unsigned int x)
+static void
+elf_eident(struct buffer *input, Elf64_Ehdr *ehdr)
 {
-	return swab32(x);
+	memmove(ehdr->e_ident, input->data, sizeof(ehdr->e_ident));
+	input->data += sizeof(ehdr->e_ident);
+	input->size -= sizeof(ehdr->e_ident);
 }
 
-unsigned int (*elf32_to_native) (unsigned int) = idemp;
 
-/* returns size of result, or -1 if error */
-int parse_elf_to_stage(const struct buffer *input, struct buffer *output,
-		       comp_algo algo, uint32_t *location)
+static void
+elf_ehdr(struct buffer *input, Elf64_Ehdr *ehdr, struct xdr *xdr, int bit64)
 {
-	Elf32_Phdr *phdr;
-	Elf32_Ehdr *ehdr = (Elf32_Ehdr *)input->data;
-	char *header, *buffer;
-
-	int headers;
-	int i;
-	struct cbfs_stage *stage;
-	unsigned int data_start, data_end, mem_end;
+	ehdr->e_type = xdr->get16(input);
+	ehdr->e_machine = xdr->get16(input);
+	ehdr->e_version = xdr->get32(input);
+	if (bit64){
+		ehdr->e_entry = xdr->get64(input);
+		ehdr->e_phoff = xdr->get64(input);
+		ehdr->e_shoff = xdr->get64(input);
+	} else {
+		ehdr->e_entry = xdr->get32(input);
+		ehdr->e_phoff = xdr->get32(input);
+		ehdr->e_shoff = xdr->get32(input);
+	}
+	ehdr->e_flags = xdr->get32(input);
+	ehdr->e_ehsize = xdr->get16(input);
+	ehdr->e_phentsize = xdr->get16(input);
+	ehdr->e_phnum = xdr->get16(input);
+	ehdr->e_shentsize = xdr->get16(input);
+	ehdr->e_shnum = xdr->get16(input);
+	ehdr->e_shstrndx = xdr->get16(input);
+}
 
-	int elf_bigendian = 0;
+static void
+elf_phdr(struct buffer *pinput, Elf64_Phdr *phdr,
+	 int entsize, struct xdr *xdr, int bit64)
+{
+	/*
+	 * The entsize need not be sizeof(*phdr).
+	 * Hence, it is easier to keep a copy of the input,
+	 * as the xdr functions may not advance the input
+	 * pointer the full entsize; rather than get tricky
+	 * we just advance it below.
+	 */
+	struct buffer input = *pinput;
+	if (bit64){
+		phdr->p_type = xdr->get32(&input);
+		phdr->p_flags = xdr->get32(&input);
+		phdr->p_offset = xdr->get64(&input);
+		phdr->p_vaddr = xdr->get64(&input);
+		phdr->p_paddr = xdr->get64(&input);
+		phdr->p_filesz = xdr->get64(&input);
+		phdr->p_memsz = xdr->get64(&input);
+		phdr->p_align = xdr->get64(&input);
+	} else {
+		phdr->p_type = xdr->get32(&input);
+		phdr->p_offset = xdr->get32(&input);
+		phdr->p_vaddr = xdr->get32(&input);
+		phdr->p_paddr = xdr->get32(&input);
+		phdr->p_filesz = xdr->get32(&input);
+		phdr->p_memsz = xdr->get32(&input);
+		phdr->p_flags = xdr->get32(&input);
+		phdr->p_align = xdr->get32(&input);
+	}
+	pinput->size -= entsize;
+	pinput->data += entsize;
+}
 
-	comp_func_ptr compress = compression_function(algo);
-	if (!compress)
-		return -1;
+/* Get the headers from the buffer.
+ * Return -1 in the event of an error.
+ */
+static int
+elf_headers(const struct buffer *pinput, Elf64_Ehdr *ehdr, Elf64_Phdr **pphdr)
+{
+	int i;
+	struct xdr *xdr = &xdr_le;
+	int bit64 = 0;
+	struct buffer input = *(struct buffer *)pinput;
+	struct buffer phdr_buf;
+	Elf64_Phdr *phdr;
 
-	DEBUG("start: parse_elf_to_stage(location=0x%x)\n", *location);
-	if (!iself((unsigned char *)input->data)) {
+	if (!iself((unsigned char *)pinput->data)) {
 		ERROR("The stage file is not in ELF format!\n");
 		return -1;
 	}
 
+	elf_eident(&input, ehdr);
+	bit64 = ehdr->e_ident[EI_CLASS] == ELFCLASS64;
+	/* Assume LE unless we are sure otherwise.
+	 * We're not going to take on the task of
+	 * fully validating the ELF file. That way
+	 * lies madness.
+	 */
+	if (ehdr->e_ident[EI_DATA] == ELFDATA2MSB)
+		xdr = &xdr_be;
+
+	elf_ehdr(&input, ehdr, xdr, bit64);
+
 	// The tool may work in architecture-independent way.
 	if (arch != CBFS_ARCHITECTURE_UNKNOWN &&
 	    !((ehdr->e_machine == EM_ARM) && (arch == CBFS_ARCHITECTURE_ARMV7)) &&
@@ -76,42 +234,84 @@ int parse_elf_to_stage(const struct buffer *input, struct buffer *output,
 		return -1;
 	}
 
-	if (ehdr->e_ident[EI_DATA] == ELFDATA2MSB) {
-		elf_bigendian = 1;
+	if (pinput->size < ehdr->e_phoff){
+		ERROR("The program header offset is greater than "
+		      "the remaining file size."
+		      "%ld bytes left, program header offset is %ld \n",
+		      pinput->size, ehdr->e_phoff);
+		return -1;
 	}
-	if (elf_bigendian != is_big_endian()) {
-		elf32_to_native = swap32;
+	/* cons up an input buffer for the headers.
+	 * Note that the program headers can be anywhere,
+	 * per the ELF spec, You'd be surprised how many ELF
+	 * readers miss this little detail.
+	 */
+	phdr_buf.data = &pinput->data[ehdr->e_phoff];
+	phdr_buf.size = ehdr->e_phentsize * ehdr->e_phnum;
+	if (phdr_buf.size > (pinput->size - ehdr->e_phoff)){
+		ERROR("The file is not large enough for the program headers."
+		      "%ld bytes left, %ld bytes of headers\n",
+		      pinput->size - ehdr->e_phoff, phdr_buf.size);
+		return -1;
 	}
+	/* gather up all the phdrs.
+	 * We do them all at once because there is more
+	 * than one loop over all the phdrs.
+	 */
+	phdr = calloc(sizeof(*phdr), ehdr->e_phnum);
+	for (i = 0; i < ehdr->e_phnum; i++)
+		elf_phdr(&phdr_buf, &phdr[i], ehdr->e_phentsize, xdr, bit64);
+	*pphdr = phdr;
+	return 0;
+}
 
-	headers = ehdr->e_phnum;
-	header = (char *)ehdr;
+/* returns size of result, or -1 if error.
+ * Note that, with the new code, this function
+ * works for all elf files, not just the restricted set.
+ */
+int parse_elf_to_stage(const struct buffer *input, struct buffer *output,
+		       comp_algo algo, uint32_t *location)
+{
+	Elf64_Phdr *phdr;
+	Elf64_Ehdr ehdr;
+	char *buffer;
+	struct buffer outheader;
 
-	phdr = (Elf32_Phdr *) & header[elf32_to_native(ehdr->e_phoff)];
+	int headers;
+	int i, outlen;
+	uint32_t data_start, data_end, mem_end;
 
-	/* Now, regular headers - we only care about PT_LOAD headers,
-	 * because thats what we're actually going to load
-	 */
+	comp_func_ptr compress = compression_function(algo);
+	if (!compress)
+		return -1;
+
+	DEBUG("start: parse_elf_to_stage(location=0x%x)\n", *location);
+
+	if (elf_headers(input, &ehdr, &phdr) < 0)
+		return -1;
+
+	headers = ehdr.e_phnum;
 
-	data_start = 0xFFFFFFFF;
+	data_start = ~0;
 	data_end = 0;
 	mem_end = 0;
 
 	for (i = 0; i < headers; i++) {
 		unsigned int start, mend, rend;
 
-		if (elf32_to_native(phdr[i].p_type) != PT_LOAD)
+		if (phdr[i].p_type != PT_LOAD)
 			continue;
 
 		/* Empty segments are never interesting */
-		if (elf32_to_native(phdr[i].p_memsz) == 0)
+		if (phdr[i].p_memsz == 0)
 			continue;
 
 		/* BSS */
 
-		start = elf32_to_native(phdr[i].p_paddr);
+		start = phdr[i].p_paddr;
 
-		mend = start + elf32_to_native(phdr[i].p_memsz);
-		rend = start + elf32_to_native(phdr[i].p_filesz);
+		mend = start + phdr[i].p_memsz;
+		rend = start + phdr[i].p_filesz;
 
 		if (start < data_start)
 			data_start = start;
@@ -128,8 +328,9 @@ int parse_elf_to_stage(const struct buffer *input, struct buffer *output,
 	}
 
 	if (data_end <= data_start) {
-		ERROR("data ends before it starts. Make sure the "
-			"ELF file is correct and resides in ROM space.\n");
+		ERROR("data ends (%08lx) before it starts (%08lx). Make sure "
+		      "the ELF file is correct and resides in ROM space.\n",
+		      (unsigned long)data_end, (unsigned long)data_start);
 		exit(1);
 	}
 
@@ -146,25 +347,39 @@ int parse_elf_to_stage(const struct buffer *input, struct buffer *output,
 	for (i = 0; i < headers; i++) {
 		unsigned int l_start, l_offset = 0;
 
-		if (elf32_to_native(phdr[i].p_type) != PT_LOAD)
+		if (phdr[i].p_type != PT_LOAD)
 			continue;
 
-		if (elf32_to_native(phdr[i].p_memsz) == 0)
+		if (phdr[i].p_memsz == 0)
 			continue;
 
-		l_start = elf32_to_native(phdr[i].p_paddr);
+		l_start = phdr[i].p_paddr;
 		if (l_start < *location) {
 			l_offset = *location - l_start;
 			l_start = *location;
 		}
 
+		/* A legal ELF file can have a program header with
+		 * non-zero length but zero-length file size and a
+		 * non-zero offset which, added together, are > than
+		 * input->size (i.e. the total file size).  So we need
+		 * to not even test in the case that p_filesz is zero.
+		 */
+		if (! phdr[i].p_filesz)
+			continue;
+		if (input->size < (phdr[i].p_offset + phdr[i].p_filesz)){
+			ERROR("Underflow copying out the segment."
+			      "File has %ld bytes left, segment end is %ld\n",
+			      input->size, phdr[i].p_offset + phdr[i].p_filesz);
+			return -1;
+		}
 		memcpy(buffer + (l_start - data_start),
-		       &header[elf32_to_native(phdr[i].p_offset)+l_offset],
-		       elf32_to_native(phdr[i].p_filesz)-l_offset);
+		       &input->data[phdr[i].p_offset + l_offset],
+		       phdr[i].p_filesz - l_offset);
 	}
 
 	/* Now make the output buffer */
-	if (buffer_create(output, sizeof(*stage) + data_end - data_start,
+	if (buffer_create(output, sizeof(struct cbfs_stage) + data_end - data_start,
 			  input->name) != 0) {
 		ERROR("Unable to allocate memory: %m\n");
 		free(buffer);
@@ -172,19 +387,31 @@ int parse_elf_to_stage(const struct buffer *input, struct buffer *output,
 	}
 	memset(output->data, 0, output->size);
 
-	stage = (struct cbfs_stage *)output->data;
-
-	stage->load = data_start; /* FIXME: htonll */
-	stage->memlen = mem_end - data_start;
-	stage->compression = algo;
-	stage->entry = ehdr->e_entry; /* FIXME: htonll */
-
-	compress(buffer, data_end - data_start, (output->data + sizeof(*stage)),
-		 (int *)&stage->len);
+	/* Compress the data, at which point we'll know information
+	 * to fill out the header. This seems backward but it works because
+	 * - the output header is a known size (not always true in many xdr's)
+	 * - we do need to know the compressed output size first
+	 */
+	compress(buffer, data_end - data_start,
+		 (output->data + sizeof(struct cbfs_stage)),
+		 &outlen);
 	free(buffer);
 
+	/* Set up for output marshaling. */
+	outheader.data = output->data;
+	outheader.size = 0;
+	/* N.B. The original plan was that SELF data was B.E.
+	 * but: this is all L.E.
+	 * Maybe we should just change the spec.
+	 */
+	xdr_le.put32(&outheader, algo);
+	xdr_le.put64(&outheader, ehdr.e_entry);
+	xdr_le.put64(&outheader, data_start);
+	xdr_le.put32(&outheader, outlen);
+	xdr_le.put32(&outheader, mem_end - data_start);
+
 	if (*location)
 		*location -= sizeof(struct cbfs_stage);
-	output->size = sizeof(*stage) + stage->len;
+	output->size = sizeof(struct cbfs_stage) + outlen;
 	return 0;
 }
diff --git a/util/cbfstool/cbfs_image.c b/util/cbfstool/cbfs_image.c
index 401654e999..2cd0c7a5a9 100644
--- a/util/cbfstool/cbfs_image.c
+++ b/util/cbfstool/cbfs_image.c
@@ -69,7 +69,7 @@ static uint32_t align_up(uint32_t value, uint32_t align)
 	return value;
 }
 
-uint32_t lookup_type_by_name(const struct typedesc_t *desc, const char *name,
+static uint32_t lookup_type_by_name(const struct typedesc_t *desc, const char *name,
 			     uint32_t default_value)
 {
 	int i;
@@ -79,7 +79,7 @@ uint32_t lookup_type_by_name(const struct typedesc_t *desc, const char *name,
 	return default_value;
 }
 
-const char *lookup_name_by_type(const struct typedesc_t *desc, uint32_t type,
+static const char *lookup_name_by_type(const struct typedesc_t *desc, uint32_t type,
 				const char *default_value)
 {
 	int i;
@@ -139,7 +139,7 @@ static int cbfs_fix_legacy_size(struct cbfs_image *image)
 }
 
 int cbfs_image_create(struct cbfs_image *image,
-		      uint32_t arch,
+		      uint32_t myarch,
 		      size_t size,
 		      uint32_t align,
 		      struct buffer *bootblock,
@@ -206,7 +206,7 @@ int cbfs_image_create(struct cbfs_image *image,
 	header->bootblocksize = htonl(bootblock->size);
 	header->align = htonl(align);
 	header->offset = htonl(entries_offset);
-	header->architecture = htonl(arch);
+	header->architecture = htonl(myarch);
 
 	// Prepare entries
 	if (align_up(entries_offset, align) != entries_offset) {
@@ -356,10 +356,10 @@ int cbfs_add_entry(struct cbfs_image *image, struct buffer *buffer,
 
 	if (IS_TOP_ALIGNED_ADDRESS(content_offset)) {
 		// legacy cbfstool takes top-aligned address.
-		uint32_t romsize = ntohl(image->header->romsize);
+		uint32_t theromsize = ntohl(image->header->romsize);
 		INFO("Converting top-aligned address 0x%x to offset: 0x%x\n",
-		     content_offset, content_offset + romsize);
-		content_offset += romsize;
+		     content_offset, content_offset + theromsize);
+		content_offset += theromsize;
 	}
 
 	// Merge empty entries.
@@ -488,7 +488,7 @@ int cbfs_export_entry(struct cbfs_image *image, const char *entry_name,
 
 	buffer.data = CBFS_SUBHEADER(entry);
 	buffer.size = ntohl(entry->len);
-	buffer.name = "(cbfs_export_entry)";
+	buffer.name = (char *)"(cbfs_export_entry)";
 	if (buffer_write_file(&buffer, filename) != 0) {
 		ERROR("Failed to write %s into %s.\n",
 		      entry_name, filename);
@@ -793,16 +793,6 @@ int cbfs_is_valid_entry(struct cbfs_image *image, struct cbfs_file *entry)
 		       sizeof(entry->magic)) == 0);
 }
 
-int cbfs_init_entry(struct cbfs_file *entry,
-		    struct buffer *buffer)
-{
-	memset(entry, 0, sizeof(*entry));
-	memcpy(entry->magic, CBFS_FILE_MAGIC, sizeof(entry->magic));
-	entry->len = htonl(buffer->size);
-	entry->offset = htonl(sizeof(*entry) + strlen(buffer->name) + 1);
-	return 0;
-}
-
 int cbfs_create_empty_entry(struct cbfs_image *image, struct cbfs_file *entry,
 		      size_t len, const char *name)
 {
diff --git a/util/cbfstool/common.c b/util/cbfstool/common.c
index 03345df1eb..8f38a4a27d 100644
--- a/util/cbfstool/common.c
+++ b/util/cbfstool/common.c
@@ -144,10 +144,13 @@ void *loadfile(const char *filename, uint32_t * romsize_p, void *content,
 	return content;
 }
 
-static struct cbfs_header *master_header;
+/* N.B.: there are declarations here that were shadowed in functions.
+ * Hence the rather clumsy cbfstool_ prefixes.
+ */
+static struct cbfs_header *cbfstool_master_header;
 static uint32_t phys_start, phys_end, align;
 uint32_t romsize;
-void *offset;
+void *cbfstool_offset;
 uint32_t arch = CBFS_ARCHITECTURE_UNKNOWN;
 
 static struct {
@@ -194,19 +197,19 @@ int find_master_header(void *romarea, size_t size)
 {
 	size_t offset;
 
-	if (master_header)
+	if (cbfstool_master_header)
 		return 0;
 
 	for (offset = 0; offset < size - sizeof(struct cbfs_header); offset++) {
 		struct cbfs_header *tmp = romarea + offset;
 
 		if (tmp->magic == ntohl(CBFS_HEADER_MAGIC)) {
-			master_header = tmp;
+			cbfstool_master_header = tmp;
 			break;
 		}
 	}
 
-	return master_header ? 0 : 1;
+	return cbfstool_master_header ? 0 : 1;
 }
 
 void recalculate_rom_geometry(void *romarea)
@@ -217,25 +220,25 @@ void recalculate_rom_geometry(void *romarea)
 	}
 
 	/* Update old headers */
-	if (master_header->version == CBFS_HEADER_VERSION1 &&
-	    ntohl(master_header->architecture) == CBFS_ARCHITECTURE_UNKNOWN) {
+	if (cbfstool_master_header->version == CBFS_HEADER_VERSION1 &&
+	    ntohl(cbfstool_master_header->architecture) == CBFS_ARCHITECTURE_UNKNOWN) {
 		DEBUG("Updating CBFS master header to version 2\n");
-		master_header->architecture = htonl(CBFS_ARCHITECTURE_X86);
+		cbfstool_master_header->architecture = htonl(CBFS_ARCHITECTURE_X86);
 	}
 
-	arch = ntohl(master_header->architecture);
+	arch = ntohl(cbfstool_master_header->architecture);
 
 	switch (arch) {
 	case CBFS_ARCHITECTURE_ARMV7:
-		offset = romarea;
-		phys_start = (0 + ntohl(master_header->offset)) & 0xffffffff;
+		cbfstool_offset = romarea;
+		phys_start = (0 + ntohl(cbfstool_master_header->offset)) & 0xffffffff;
 		phys_end = romsize & 0xffffffff;
 		break;
 	case CBFS_ARCHITECTURE_X86:
-		offset = romarea + romsize - 0x100000000ULL;
-		phys_start = (0 - romsize + ntohl(master_header->offset)) &
+		cbfstool_offset = romarea + romsize - 0x100000000ULL;
+		phys_start = (0 - romsize + ntohl(cbfstool_master_header->offset)) &
 				0xffffffff;
-		phys_end = (0 - ntohl(master_header->bootblocksize) -
+		phys_end = (0 - ntohl(cbfstool_master_header->bootblocksize) -
 		     sizeof(struct cbfs_header)) & 0xffffffff;
 		break;
 	default:
@@ -243,7 +246,7 @@ void recalculate_rom_geometry(void *romarea)
 		exit(1);
 	}
 
-	align = ntohl(master_header->align);
+	align = ntohl(cbfstool_master_header->align);
 }
 
 void *loadrom(const char *filename)
@@ -351,8 +354,8 @@ void print_cbfs_directory(const char *filename)
 	printf
 		("%s: %d kB, bootblocksize %d, romsize %d, offset 0x%x\n"
 		 "alignment: %d bytes, architecture: %s\n\n",
-		 basename(name), romsize / 1024, ntohl(master_header->bootblocksize),
-		 romsize, ntohl(master_header->offset), align, arch_to_string(arch));
+		 basename(name), romsize / 1024, ntohl(cbfstool_master_header->bootblocksize),
+		 romsize, ntohl(cbfstool_master_header->offset), align, arch_to_string(arch));
 	free(name);
 	printf("%-30s %-10s %-12s Size\n", "Name", "Offset", "Type");
 	uint32_t current = phys_start;
@@ -364,12 +367,12 @@ void print_cbfs_directory(const char *filename)
 		struct cbfs_file *thisfile =
 			(struct cbfs_file *)phys_to_virt(current);
 		uint32_t length = ntohl(thisfile->len);
-		char *fname = (char *)(phys_to_virt(current) + sizeof(struct cbfs_file));
+		const char *fname = (char *)(phys_to_virt(current) + sizeof(struct cbfs_file));
 		if (strlen(fname) == 0)
 			fname = "(empty)";
 
 		printf("%-30s 0x%-8x %-12s %d\n", fname,
-		       current - phys_start + ntohl(master_header->offset),
+		       current - phys_start + ntohl(cbfstool_master_header->offset),
 		       strfiletype(ntohl(thisfile->type)), length);
 
 		/* note the components of the subheader are in host order ... */
@@ -664,7 +667,7 @@ void *create_cbfs_file(const char *filename, void *data, uint32_t * datasize,
 }
 
 int create_cbfs_image(const char *romfile, uint32_t _romsize,
-		const char *bootblock, uint32_t align, uint32_t offs)
+		const char *bootblock, uint32_t create_align, uint32_t offs)
 {
 	uint32_t bootblocksize = 0;
 	struct cbfs_header *master_header;
@@ -679,8 +682,8 @@ int create_cbfs_image(const char *romfile, uint32_t _romsize,
 	}
 	memset(romarea, 0xff, romsize);
 
-	if (align == 0)
-		align = 64;
+	if (create_align == 0)
+		create_align = 64;
 
 	bootblk = loadfile(bootblock, &bootblocksize,
 				romarea + romsize, SEEK_END);
@@ -695,7 +698,7 @@ int create_cbfs_image(const char *romfile, uint32_t _romsize,
 	switch (arch) {
 	case CBFS_ARCHITECTURE_ARMV7:
 		/* Set up physical/virtual mapping */
-		offset = romarea;
+		cbfstool_offset = romarea;
 
 		/*
 		 * The initial jump instruction and bootblock will be placed
@@ -746,7 +749,7 @@ int create_cbfs_image(const char *romfile, uint32_t _romsize,
 
 	case CBFS_ARCHITECTURE_X86:
 		// Set up physical/virtual mapping
-		offset = romarea + romsize - 0x100000000ULL;
+		cbfstool_offset = romarea + romsize - 0x100000000ULL;
 
 		loadfile(bootblock, &bootblocksize, romarea + romsize,
 			 SEEK_END);
diff --git a/util/cbfstool/common.h b/util/cbfstool/common.h
index 6e12fcb064..ed75a7fd02 100644
--- a/util/cbfstool/common.h
+++ b/util/cbfstool/common.h
@@ -62,7 +62,7 @@ int buffer_write_file(struct buffer *buffer, const char *filename);
 /* Destroys a memory buffer. */
 void buffer_delete(struct buffer *buffer);
 
-extern void *offset;
+extern void *cbfstool_offset;
 extern uint32_t romsize;
 extern int host_bigendian;
 extern uint32_t arch;
@@ -72,12 +72,12 @@ uint32_t string_to_arch(const char *arch_string);
 
 static inline void *phys_to_virt(uint32_t addr)
 {
-	return offset + addr;
+	return cbfstool_offset + addr;
 }
 
 static inline uint32_t virt_to_phys(void *addr)
 {
-	return (unsigned long)(addr - offset) & 0xffffffff;
+	return (unsigned long)(addr - cbfstool_offset) & 0xffffffff;
 }
 
 #define ALIGN(val, by) (((val) + (by)-1)&~((by)-1))
@@ -124,7 +124,6 @@ int add_file_to_cbfs(void *content, uint32_t contentsize, uint32_t location);
 int remove_file_from_cbfs(const char *filename);
 void print_cbfs_directory(const char *filename);
 int extract_file_from_cbfs(const char *filename, const char *payloadname, const char *outpath);
-int remove_file_from_cbfs(const char *filename);
 
 uint32_t cbfs_find_location(const char *romfile, uint32_t filesize,
 			    const char *filename, uint32_t align);
@@ -132,5 +131,30 @@ uint32_t cbfs_find_location(const char *romfile, uint32_t filesize,
 void print_supported_filetypes(void);
 
 #define ARRAY_SIZE(a) (int)(sizeof(a) / sizeof((a)[0]))
+/* lzma/lzma.c */
+void do_lzma_compress(char *in, int in_len, char *out, int *out_len);
+void do_lzma_uncompress(char *dst, int dst_len, char *src, int src_len);
+/* xdr.c */
+struct xdr {
+	uint16_t (*get16)(struct buffer *input);
+	uint32_t (*get32)(struct buffer *input);
+	uint64_t (*get64)(struct buffer *input);
+	void (*put16)(struct buffer *input, uint16_t val);
+	void (*put32)(struct buffer *input, uint32_t val);
+	void (*put64)(struct buffer *input, uint64_t val);
+};
+
+/* common.c */
+
+int find_master_header(void *romarea, size_t size);
+void recalculate_rom_geometry(void *romarea);
+const char *strfiletype(uint32_t number);
+
+/* cbfs_image.c */
+uint32_t get_cbfs_entry_type(const char *name, uint32_t default_value);
+const char *get_cbfs_entry_type_name(uint32_t type);
+uint32_t get_cbfs_compression(const char *name, uint32_t unknown);
+
+extern struct xdr xdr_le, xdr_be;
 
 #endif
diff --git a/util/cbfstool/compress.c b/util/cbfstool/compress.c
index 9ea1487ff9..38fa03dbed 100644
--- a/util/cbfstool/compress.c
+++ b/util/cbfstool/compress.c
@@ -26,8 +26,6 @@
 #include <stdio.h>
 #include "common.h"
 
-void do_lzma_compress(char *in, int in_len, char *out, int *out_len);
-
 static void lzma_compress(char *in, int in_len, char *out, int *out_len)
 {
 	do_lzma_compress(in, in_len, out, out_len);
diff --git a/util/cbfstool/fit.c b/util/cbfstool/fit.c
index c76ba480ad..f15ccf510b 100644
--- a/util/cbfstool/fit.c
+++ b/util/cbfstool/fit.c
@@ -104,9 +104,9 @@ static inline int fit_entry_type(struct fit_entry *entry)
  * in the host address space at [4G - romsize -> 4G). It also assume all
  * pointers have values within this address range.
  */
-static inline int ptr_to_offset(uint32_t romsize, uint32_t host_ptr)
+static inline int ptr_to_offset(uint32_t theromsize, uint32_t host_ptr)
 {
-	return (int)(romsize + host_ptr);
+	return (int)(theromsize + host_ptr);
 }
 
 /*
@@ -114,9 +114,9 @@ static inline int ptr_to_offset(uint32_t romsize, uint32_t host_ptr)
  * in the host address space at [4G - romsize -> 4G). It also assume all
  * pointers have values within this address range.
  */
-static inline uint32_t offset_to_ptr(uint32_t romsize, int offset)
+static inline uint32_t offset_to_ptr(uint32_t theromsize, int offset)
 {
-	return -(romsize - (uint32_t )offset);
+	return -(theromsize - (uint32_t )offset);
 }
 
 static struct fit_table *locate_fit_table(struct cbfs_image *image)
diff --git a/util/cbfstool/xdr.c b/util/cbfstool/xdr.c
new file mode 100644
index 0000000000..d779675cd5
--- /dev/null
+++ b/util/cbfstool/xdr.c
@@ -0,0 +1,140 @@
+ /*
+ * cbfstool, CLI utility for CBFS file manipulation
+ *
+ * Copyright 2013 Google Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA, 02110-1301 USA
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <ctype.h>
+#include <unistd.h>
+#include <stdint.h>
+#include "common.h"
+
+/* The assumption in all this code is that we're given a pointer to enough data.
+ * Hence, we do not check for underflow.
+ */
+static uint8_t get8(struct buffer *input)
+{
+	uint8_t ret = *input->data++;
+	input->size--;
+	return ret;
+}
+
+static uint16_t get16be(struct buffer *input)
+{
+	uint16_t ret;
+	ret = get8(input) << 8;
+	ret |= get8(input);
+	return ret;
+}
+
+static uint32_t get32be(struct buffer *input)
+{
+	uint32_t ret;
+	ret = get16be(input) << 16;
+	ret |= get16be(input);
+	return ret;
+}
+
+static uint64_t get64be(struct buffer *input)
+{
+	uint64_t ret;
+	ret = get32be(input);
+	ret <<= 32;
+	ret |= get32be(input);
+	return ret;
+}
+
+static void put8(struct buffer *input, uint8_t val)
+{
+	input->data[input->size] = val;
+	input->size++;
+}
+
+static void put16be(struct buffer *input, uint16_t val)
+{
+	put8(input, val >> 8);
+	put8(input, val);
+}
+
+static void put32be(struct buffer *input, uint32_t val)
+{
+	put16be(input, val >> 16);
+	put16be(input, val);
+}
+
+static void put64be(struct buffer *input, uint64_t val)
+{
+	put32be(input, val >> 32);
+	put32be(input, val);
+}
+
+static uint16_t get16le(struct buffer *input)
+{
+	uint16_t ret;
+	ret = get8(input);
+	ret |= get8(input) << 8;
+	return ret;
+}
+
+static uint32_t get32le(struct buffer *input)
+{
+	uint32_t ret;
+	ret = get16le(input);
+	ret |= get16le(input) << 16;
+	return ret;
+}
+
+static uint64_t get64le(struct buffer *input)
+{
+	uint64_t ret;
+	uint32_t low;
+	low = get32le(input);
+	ret = get32le(input);
+	ret <<= 32;
+	ret |= low;
+	return ret;
+}
+
+static void put16le(struct buffer *input, uint16_t val)
+{
+	put8(input, val);
+	put8(input, val >> 8);
+}
+
+static void put32le(struct buffer *input, uint32_t val)
+{
+	put16le(input, val);
+	put16le(input, val >> 16);
+}
+
+static void put64le(struct buffer *input, uint64_t val)
+{
+	put32le(input, val);
+	put32le(input, val >> 32);
+}
+
+struct xdr xdr_be = {
+	get16be, get32be, get64be,
+	put16be, put32be, put64be
+};
+
+struct xdr xdr_le = {
+	get16le, get32le, get64le,
+	put16le, put32le, put64le
+};