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/*-
* nslu2_image.cc
* Return the bytes of an NSLU2 image, constructed on the fly if
* necessary.
*/
#include <stdexcept>
#include <cstring>
#include <fstream>
#include <cerrno>
#include "nslu2_image.h"
namespace NSLU2Image {
/* This code requires a complete read of the given buffer each
* time.
*/
void SafeRead(std::ifstream *stream, char *buffer, size_t length, const char *name) {
while (length > 0) {
if (stream->eof())
throw NSLU2Image::FileError(SizeError, name, errno);
stream->read(buffer, length);
int count(stream->gcount());
length -= count;
buffer += count;
if (stream->fail())
throw FileError(ReadError, name, errno);
}
}
void SafeSeek(std::ifstream *stream, int offset, const char *name) {
stream->seekg(offset, std::ios::beg);
if (!stream->good())
throw NSLU2Image::FileError(SizeError, name, errno);
}
class RealImage : public Image {
public:
RealImage(bool r, const char *i) : reprogram(r) {
image.open(i, std::ios::in | std::ios::binary);
if (!image.good())
throw FileError(OpenError, i, errno);
Validate(i);
Rewind();
}
virtual ~RealImage() {
}
/* Get the next block of bytes, returns an address and length.
*/
virtual void GetBytes(char *buffer, size_t buffer_length,
int &address, int &length) {
address = image.tellg();
length = buffer_length;
if (address+length > NSLU2Protocol::FlashSize)
length = NSLU2Protocol::FlashSize-address;
if (length > 0)
SafeRead(&image, buffer, length, "image (read)");
}
/* Rewind to the start of the image (or the Kernel if not
* doing a complete reprogram).
*/
virtual void Rewind(void) {
SafeSeek(&image, reprogram ? 0 : NSLU2Protocol::BaseAddress,
"image (seek)");
}
private:
/* Validate that this really is an image file. */
void Validate(const char *i) {
char signature[8];
SafeSeek(&image, NSLU2Protocol::FlashSize-8, i);
SafeRead(&image, signature, 8, i);
if (memcmp(signature, "eRcOmM", 6) != 0)
throw NSLU2Image::FileError(DataError, i, 0);
}
bool reprogram;
std::ifstream image;
};
class SynthesiseImage : public Image {
public:
SynthesiseImage(char kernel_sex, char data_sex, char directory_sex,
const char *k, bool noramdisk,
const char *ram, const char *root, const char *f,
unsigned short product_id, unsigned short protocol_id,
unsigned short firmware_version, unsigned short extra_version);
virtual ~SynthesiseImage() {
}
/* Get the next block of bytes, returns an address and length, false if
* there is a problem.
*/
virtual void GetBytes(char *buffer, size_t buffer_length,
int &address, int &length);
/* Rewind to the start of the image data. */
virtual void Rewind(void) {
flash_address = 0x60000;
}
private:
/* Return the size of a file. */
int SizeOf(std::ifstream &file) {
if (file) {
file.seekg(0, std::ios::end);
const int length(file.tellg());
if (!file.fail())
return length;
}
throw FileError(ReadError, "SizeOf", errno);
}
typedef enum {
RedBoot,
SysConf,
Kernel,
Ramdisk,
Flashdisk,
FISDirectory,
} FlashType;
/* Write a 32 bit big endian value */
inline void Write32BE(char *p, unsigned long v) {
*p++ = v >> 24;
*p++ = v >> 16;
*p++ = v >> 8;
*p++ = v;
}
/* Write a 32 bit little endian value */
inline void Write32LE(char *p, unsigned long v) {
*p++ = v;
*p++ = v >> 8;
*p++ = v >> 16;
*p++ = v >> 24;
}
/* Write a 32 bit image-endian value - the actual test is on
* the kernel endianness, not the data endianness, because this
* is a value which is written into the data (byte stream) in a
* format the kernel is expected to recognise!
*/
inline void Write32FIS(char *p, unsigned long v) {
if (little_endian_fis)
Write32LE(p, v);
else
Write32BE(p, v);
}
inline unsigned long Read32BE(const char *p) {
return ((0xff & p[0]) << 24) +
((0xff & p[1]) << 16) +
((0xff & p[2]) << 8) +
((0xff & p[3]) );
}
inline unsigned long Read32LE(const char *p) {
return ((0xff & p[3]) << 24) +
((0xff & p[2]) << 16) +
((0xff & p[1]) << 8) +
((0xff & p[0]) );
}
/* Make a new entry - this must be called in order because it
* calculates the base flash address of this entry (on the next
* 0x20000 byte boundary) using flash_address and returns a
* pointer to the 36 byte data block which is constructed at the
* next position in the buffer.
*
* In: name of entry and actual length of data in the entry.
* size of partition, or 0 to calculate from length
* Out: pointer to FIS directory entry (in buffer),
* flash_address set to the base address of the partition
* buffer_pointer advanced over new block of FIS data
*/
const char *MakeFISEntry(const char *name, int size, int length) {
char *b = buffer+buffer_pointer;
buffer_pointer += 36;
std::memset(b, 255, 36);
std::strcpy(b+ 0, name);
flash_address = (flash_address + 0x1ffff) & ~0x1ffff;
Write32FIS(b+16, 0x50000000 | flash_address);
/* b+20: Do not set memory address */
Write32FIS(b+24, size != 0 ? size : (length+0x1ffff) & ~0x1ffff);
/* b+28: Do not set entry point */
Write32FIS(b+32, length);
return b;
}
std::ifstream kernel; /* The files, where provided */
std::ifstream ramdisk;
std::ifstream rootfs;
std::ifstream payload;
int segment_count; /* Count of Segment entries used */
int buffer_pointer; /* Index of next free slot in buffer */
int flash_address; /* Current flash address */
bool little_endian_fis; /* Build a little endian FIS directory */
bool pdp_endian; /* half-word, not quad-word, swap the data */
/* The flash partitions have a data header then data from a file,
* represent this as an array of Segment entries, up to 2x5 for
* the actual partitions, 6 FIS entries (all data), a payload and
* the trailer - 17, allow for checksums in the future by
* allocating 32 entries (6 extra for checksums plus 7 spare).
*/
struct Segment {
int address;
int length;
bool swap; /* quad byte swap */
bool swab; /* two byte swap */
const char* data;
std::ifstream* file;
} segments[32];
/* The FIS directory consists of up to 6 entries in this implementation.
* Because the checksum is not currently computed each entry is a block
* of 36 contiguous bytes.
*
* A buffer is required for the computed FIS entries (36 bytes x 6),
* the trailer (16 bytes) and some bytes per partition - allow 16 (x6).
* This is a total of 328 bytes, 512 bytes allows for some extra data
* (e.g. the checksums) if required in the future.
*/
char buffer[512];
};
};
/*-
* r(reprogram) - write the whole image to flash (boot loader too)
* i(image) - the image to write
*
* Writes exactly the given image to flash (no checking!)
*/
NSLU2Image::Image *NSLU2Image::Image::MakeImage(bool reprogram, const char *image) {
return new RealImage(reprogram, image);
}
/*-
* kernel_sex - byte sex of kernel (determines FIS sex)
* data_sex - byte sex of data (l, b or p for PDP!)
* directory_sex - byte sex of numbers in FIS directory
* k(kernel) - file containing a kernel image
* nr(noramdisk) - causes the image to contain a zero length ramdisk
* ram(ramdisk) - the ramdisk image (if nr this is just a payload)
* root(rootfs) - the jffs2 rootfs image
* fis(fis_payload) - payload to follow the FIS Directory.
*
* Synthesises an image and writes this to flash (never overwrites the
* boot loader).
*/
NSLU2Image::SynthesiseImage::SynthesiseImage(char kernel_sex, char data_sex,
char directory_sex,
const char *k, bool noramdisk, const char *ram,
const char *root, const char *f, unsigned short product_id,
unsigned short protocol_id, unsigned short firmware_version,
unsigned short extra_version) :
little_endian_fis(directory_sex == 'l'),
segment_count(0), buffer_pointer(0), flash_address(0) {
const char *fis[8];
bool swap(data_sex == 'l');
bool swab(data_sex == 'p');
/* Use open to open the files, not the constructor, because the arguments
* may be null, this also means that the ifstream can be used to determine
* whether or not the file exists.
*
* Build the FIS Directory using the sizes of the above files and knowledge
* of the RedBoot and SysConf partition layout.
*/
fis[0] = MakeFISEntry("RedBoot", 0x40000, 0x40000);
flash_address += 0x40000;
fis[1] = MakeFISEntry("SysConf", 0x20000, 0x20000);
flash_address += 0x20000;
int fis_count(2);
if (k != 0) {
/* The LinkSys RedBoot modifications hardwire the address of
* the ramdisk to 0x160000, it is sufficient for the four
* bytes at that address to contain 0 (then nothing will be
* copied), but it is difficult to arrange for this to happen
* (perhaps by padding the LZ stream in the kernel). For
* the moment this code fixes the kernel size at 0x100000.
*/
kernel.open(k, std::ios::in | std::ios::binary);
if (!kernel.good())
throw FileError(OpenError, k, errno);
const int s(SizeOf(kernel));
if (s+16 > 0x100000)
throw FileError(SizeError, k, 0);
fis[fis_count++] = MakeFISEntry("Kernel", 0x100000, 16+s);
Write32BE(buffer+buffer_pointer, s);
segments[segment_count].address = flash_address;
segments[segment_count].length = 4;
segments[segment_count].swap = false;
segments[segment_count].swab = false;
segments[segment_count].data = buffer+buffer_pointer;
segments[segment_count++].file = 0;
buffer_pointer += 4;
if (s > 0) {
/* An LE kernel is written on the assumption that byte 0
* will end in in the LSB, but RedBoot will both write
* and subsequently read it as a set of BE values - byte 0
* goes into the MSB of the first word, so we need to
* quad-byte-swap
*/
segments[segment_count].address = flash_address+16;
segments[segment_count].length = s;
segments[segment_count].swap = kernel_sex == 'l';
segments[segment_count].swab = false;
segments[segment_count].data = 0;
segments[segment_count++].file = &kernel;
}
flash_address += 0x100000;
} else
throw FileError(Required, "Kernel", 0);
/* The Ramdisk entry must always exist, although it need only be one
* block in size.
*/
{
int s(0);
if (ram != 0) {
ramdisk.open(ram, std::ios::in | std::ios::binary);
if (!ramdisk.good())
throw FileError(OpenError, ram, errno);
s = SizeOf(ramdisk);
/* The compressed ramdisk has a 16 byte header. */
if (s+16 > NSLU2Protocol::FlashSize-flash_address-0x20000)
throw FileError(SizeError, ram, 0);
}
fis[fis_count++] = MakeFISEntry("Ramdisk", 0/*calculate*/, s+16);
Write32BE(buffer+buffer_pointer, noramdisk ? 0 : s);
segments[segment_count].address = flash_address;
segments[segment_count].length = 4;
segments[segment_count].swap = false;
segments[segment_count].swab = false;
segments[segment_count].data = buffer+buffer_pointer;
segments[segment_count++].file = 0;
buffer_pointer += 4;
flash_address += 16;
if (s > 0) {
/* PDP case:
* Data is assumed to be a simple byte stream in the
* correct format. For LE RedBoot will write the first
* two bytes into the first 16 bit flash word with the
* first byte most significant. Since the first byte
* should be least significant (but still in the first
* word) we need to double-byte-swap (swab) the data.
*
* Note that this differs from the kernel primarily because
* RedBoot writes (BE) but the data is then read from an
* LE CPU. Because the Intel architecture treats the
* flash as 16 bit and does not word-swap the addresses (in
* fact the flash is effectively BE) we have to do 2 byte
* swapping.
*
* Standard case:
* Quad byte swap
*/
segments[segment_count].address = flash_address;
segments[segment_count].length = s;
segments[segment_count].swap = swap;
segments[segment_count].swab = swab;
segments[segment_count].data = 0;
segments[segment_count++].file = &ramdisk;
flash_address += s;
}
}
/* The ffs2 rootfs is optional */
if (root != 0) {
rootfs.open(root, std::ios::in | std::ios::binary);
if (!rootfs.good())
throw FileError(OpenError, root, errno);
const int s(SizeOf(rootfs));
/* The partition takes all the remaining space - it doesn't have
* to do this, but there must be some blank space for the file
* system to be useable.
*/
flash_address = (flash_address + 0x1ffff) & ~0x1ffff;
const int size(NSLU2Protocol::FlashSize-0x20000-flash_address);
/*TODO: check that there is enough space for the ffs2 parition,
* at present this just allows 0x20000, is that enough or too much?
*/
if (s+0x20000 > size)
throw FileError(SizeError, root, 0);
fis[fis_count++] = MakeFISEntry("Flashdisk", size, s);
/* The jffs2 Flashdisk parition has no header. */
if (s > 0) {
segments[segment_count].address = flash_address;
segments[segment_count].length = s;
segments[segment_count].swap = swap;
segments[segment_count].swab = swab;
segments[segment_count].data = 0;
segments[segment_count++].file = &rootfs;
flash_address += s;
}
}
/* The FIS directory is at the end of the image. */
flash_address = NSLU2Protocol::FlashSize-0x20000;
fis[fis_count] = MakeFISEntry("FIS directory", 0x20000, (fis_count+1) * 256);
for (int i(0); i<=fis_count; ++i) {
segments[segment_count].address = flash_address;
segments[segment_count].length = 36;
segments[segment_count].swap = swap;
segments[segment_count].swab = swab;
segments[segment_count].data = fis[i];
segments[segment_count++].file = 0;
flash_address += 256;
}
if (f != 0) {
/* The payload follows the last valid FIS directory entry, the directory
* is terminated by a single 255 byte (in the 'name' field), so to mark
* the payload output [255]dat[length] where [length] is the big endian
* length of the payload.
*/
payload.open(f, std::ios::in | std::ios::binary);
if (!payload.good())
throw FileError(OpenError, f, errno);
const int s(SizeOf(payload));
/* The payload fits after the last (valid) FIS entry - and must leave
* space for the 16 byte 'signature' which the NSLU2 RedBoot recognises
* as indicating a valid image and for the 8 byte payload header.
*/
if (s > 0x20000 - (fis_count+1)*256 - 16 - 8)
throw FileError(SizeError, f, 0);
/* The header is written even for a zero length payload. */
segments[segment_count].address = flash_address;
segments[segment_count].length = 8;
segments[segment_count].swap = false;
segments[segment_count].swab = false;
segments[segment_count].data = buffer+buffer_pointer;
segments[segment_count++].file = 0;
buffer[buffer_pointer++] = 255;
buffer[buffer_pointer++] = 'd';
buffer[buffer_pointer++] = 'a';
buffer[buffer_pointer++] = 't';
Write32BE(buffer+buffer_pointer, s);
buffer_pointer += 4;
flash_address += 8;
if (s > 0) {
segments[segment_count].address = flash_address;
segments[segment_count].length = s;
segments[segment_count].swap = swap;
segments[segment_count].swab = swab;
segments[segment_count].data = 0;
segments[segment_count++].file = &payload;
flash_address += s;
}
}
/* This is a sanity check. */
if (flash_address > NSLU2Protocol::FlashSize-16)
throw std::logic_error("flash address too large");
flash_address = NSLU2Protocol::FlashSize-16;
segments[segment_count].address = flash_address;
segments[segment_count].length = 15;
segments[segment_count].swap = false;
segments[segment_count].swab = false;
segments[segment_count].data = buffer+buffer_pointer;
segments[segment_count++].file = 0;
buffer[buffer_pointer++] = product_id >> 8;
buffer[buffer_pointer++] = product_id;
buffer[buffer_pointer++] = protocol_id >> 8;
buffer[buffer_pointer++] = protocol_id;
buffer[buffer_pointer++] = firmware_version >> 8;
buffer[buffer_pointer++] = firmware_version;
buffer[buffer_pointer++] = extra_version >> 8;
buffer[buffer_pointer++] = extra_version;
/* The following includes a trailing null but leaves the last byte unset. */
std::memcpy(buffer+buffer_pointer, "eRcOmM", 7);
buffer_pointer += 7;
if (buffer_pointer > sizeof buffer)
throw std::logic_error("data buffer too small");
/* Set the flash_address local back to after SysConf to start output of the
* image.
*/
Rewind();
}
void NSLU2Image::SynthesiseImage::GetBytes(char *buffer, size_t buffer_length,
int &address, int &length) {
if (buffer_length & 3)
throw std::logic_error("invalid buffer length");
/* Just go through the list, segment by segment. */
int i(0);
while (i < segment_count &&
flash_address >= segments[i].address + segments[i].length)
++i;
if (i < segment_count) {
int base(segments[i].address);
int offset(0);
if (flash_address < base)
flash_address = base;
else
offset = flash_address-base;
if (flash_address & 3)
throw std::logic_error("non-word-aligned flash address");
int len(segments[i].length - offset);
if (len > buffer_length)
len = buffer_length;
if (segments[i].data != 0)
std::memcpy(buffer, segments[i].data+offset, len);
else if (segments[i].file != 0) {
std::ifstream *pfile = segments[i].file;
SafeSeek(pfile, offset, "segment");
SafeRead(pfile, buffer, len, "segment");
} else
throw std::logic_error("no data in segment");
/* At this point the buffer must be padded to a word boundary if
* required, this is always safe because the next flash address
* will overwrite this data if necessary (and it won't do that
* because if it did the flash address itself would not be on
* a word boundary).
*/
while (len & 3)
buffer[len++] = '\xff';
/* At present expect only one of swab or swap. */
if (segments[i].swab && segments[i].swap)
throw std::logic_error("swap and swab both specified");
/* If required quad-byte-swap this data. */
if (segments[i].swap) for (int j(0); j+4<=len; j+=4) {
Write32BE(buffer+j, Read32LE(buffer+j));
}
/* Likewise for swab */
if (segments[i].swab) for (int j(0); j+2<=len; j+=2) {
char tmp(buffer[0]);
buffer[0] = buffer[1], ++buffer;
*buffer++ = tmp;
}
address = flash_address;
length = len;
flash_address += len;
} else {
address = NSLU2Protocol::FlashSize;
length = 0;
}
}
NSLU2Image::Image *NSLU2Image::Image::MakeImage(char kernel_sex, char data_sex,
char directory_sex, const char *k, bool nr,
const char *ram, const char *root, const char *fis,
unsigned short product_id, unsigned short protocol_id,
unsigned short firmware_version, unsigned short extra_version) {
return new SynthesiseImage(kernel_sex, data_sex, directory_sex,
k, nr, ram, root, fis,
product_id, protocol_id, firmware_version, extra_version);
}
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