gzip.c

EFI（Extensible Firmware Interface)是下一代BIOS

/*
 *  Copyright (C) 2001-2003 Hewlett-Packard Co.
 *	Contributed by Stephane Eranian <[e-mail]>
 *
 *  Copyright (C) 2001 Silicon Graphics, Inc.
 *      Contributed by Brent Casavant <[e-mail]>
 *
 * This file is part of the ELILO, the EFI Linux boot loader.
 *
 *  ELILO 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; either version 2, or (at your option)
 *  any later version.
 *
 *  ELILO 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 ELILO; see the file COPYING.  If not, write to the Free
 *  Software Foundation, 59 Temple Place - Suite 330, Boston, MA
 *  02111-1307, USA.
 *
 * Please check out the elilo.txt for complete documentation on how
 * to use this program.
 */

#include <efi.h>
#include <efilib.h>

#include "elf.h"
#include "elilo.h"

#include "gzip.h"

#include "private.h"
#include "setjmp.h"

#define memzero(s, n)	Memset((VOID *)(s), 0, (n))
#define memcpy(a,b,n)	Memcpy((VOID *)(a),(b),(n))

/* size of output buffer */
#define WSIZE 0x8000		/* Window size must be at least 32k, */
				/* and a power of two */
/* size of input buffer */
#define INBUFSIZE 0x8000

/*
 * gzip declarations
 */

#define OF(args)  args
#define FUNC_STATIC static

typedef unsigned char  uch;
typedef unsigned short ush;
typedef unsigned long  ulg;


typedef struct segment {
	unsigned long addr;	/* start address */
       	unsigned long offset;	/* file offset   */
       	unsigned long size;	/* file size     */
	unsigned long bss_sz;	/* BSS size      */
	UINT8	flags;	/* indicates whether to load or not */
} segment_t;

#define CHUNK_FL_VALID		0x1
#define CHUNK_FL_LOAD		0x2

#define CHUNK_CAN_LOAD(n)	chunks[(n)].flags |= CHUNK_FL_LOAD
#define CHUNK_NO_LOAD(n)	chunks[(n)].flags &= ~CHUNK_FL_LOAD
#define CHUNK_IS_LOAD(n)	(chunks[(n)].flags & CHUNK_FL_LOAD)

#define CHUNK_VALIDATE(n)	chunks[(n)].flags |= CHUNK_FL_VALID
#define CHUNK_INVALIDATE(n)	chunks[(n)].flags = 0
#define CHUNK_IS_VALID(n)	(chunks[(n)].flags & CHUNK_FL_VALID)

/*
 * static parameters to gzip helper functions
 * we cannot use paramters because API was not
 * designed that way
 */
static segment_t *chunks;	/* holds the list of segments */
static segment_t *cur_chunk;
static UINTN nchunks;
static UINTN chunk;                 /* current segment */
static UINTN input_fd;
static VOID *kernel_entry, *kernel_base, *kernel_end;

static uch *inbuf;		/* input buffer (compressed data) */
static uch *window;    		/* output buffer (uncompressed data) */
static unsigned long file_offset;	/* position in the file */

static unsigned insize = 0;  /* valid bytes in inbuf */
static unsigned inptr  = 0;   /* index of next byte to be processed in inbuf */
static unsigned outcnt = 0;  /* bytes in output buffer */

/* gzip flag byte */
#define ASCII_FLAG   0x01 /* bit 0 set: file probably ASCII text */
#define CONTINUATION 0x02 /* bit 1 set: continuation of multi-part gzip file */
#define EXTRA_FIELD  0x04 /* bit 2 set: extra field present */
#define ORIG_NAME    0x08 /* bit 3 set: original file name present */
#define COMMENT      0x10 /* bit 4 set: file comment present */
#define ENCRYPTED    0x20 /* bit 5 set: file is encrypted */
#define RESERVED     0xC0 /* bit 6,7:   reserved */

#define get_byte()  (inptr < insize ? inbuf[inptr++] : fill_inbuf())

/* Diagnostic functions */
#ifdef INFLATE_DEBUG
#  define Assert(cond,msg) {if(!(cond)) error(msg);}
int stderr;
#  define Trace(x) Print(L"line %d:\n", __LINE__);
#  define Tracev(x) {if (verbose) Print(L"line %d:\n", __LINE__) ;}
#  define Tracevv(x) {if (verbose>1) Print(L"line %d:\n", __LINE__)  ;}
#  define Tracec(c,x) {if (verbose && (c))  Print(L"line %d:\n", __LINE__) ;}
#  define Tracecv(c,x) {if (verbose>1 && (c))  Print(L"line %d:\n", __LINE__) ;}
#else
#  define Assert(cond,msg)
#  define Trace(x)
#  define Tracev(x)
#  define Tracevv(x)
#  define Tracec(c,x)
#  define Tracecv(c,x)
#endif

static int  fill_inbuf(void);
static void flush_window(void);
static void error(char *m);
static long bytes_out;

static void error(char *m);

static jmp_buf jbuf;
static int error_return;
static UINTN elf_is_big_endian;	/* true if ELF file is big endian */

static void *
gzip_malloc(int size)
{
	return (void *)alloc(size, 0);
}

static void
gzip_free(void *where)
{	
	return free(where);
}

#include "inflate.c"

/*
 * Fill the input buffer and return the first byte in it. This is called
 * only when the buffer is empty and at least one byte is really needed.
 */
int
fill_inbuf(void)
{
	INTN expected, nread;
	EFI_STATUS status;

	expected = nread = INBUFSIZE;

	status = fops_read(input_fd, inbuf, &nread);
	if (EFI_ERROR(status)) {
    		error("elilo: Read failed");
	}
	DBG_PRT((L"%s : read %d bytes of %d bytes\n", LD_NAME, nread, expected));

	insize = nread;
	inptr = 1;

	return inbuf[0];
}

/* ===========================================================================
 * Write the output window window[0..outcnt-1] and update crc and bytes_out.
 * (Used for the decompressed data only.)
 */

/*
 * Run a set of bytes through the crc shift register.  If s is a NULL
 * pointer, then initialize the crc shift register contents instead.
 * Return the current crc in either case.
 *
 * Input:
 *	S	pointer to bytes to pump through.
 *	N	number of bytes in S[].
 */
unsigned long
updcrc(unsigned char *s, unsigned n)
{
	register unsigned long c;
	/* crc is defined in inflate.c */

	if (!s) {
		c = 0xffffffffL;
	} else {
		c = crc;
		while (n--) {
			c = crc_32_tab[((int)c ^ (*s++)) & 0xff] ^ (c >> 8);
		}
	}
	crc = c;
	return c ^ 0xffffffffUL;       /* (instead of ~c for 64-bit machines) */
}


/*
 * Clear input and output buffers
 */
void
clear_bufs(void)
{
	outcnt = 0;
	inptr = 0;
	chunk = 0;
	cur_chunk = NULL;
	file_offset = 0;
}


static inline UINT64 
bswap64(UINT64 v)
{
        if(elf_is_big_endian) v = __ia64_swab64(v);
        return v;
}

static inline UINT32
bswap32(UINT32 v)
{
        if(elf_is_big_endian) v = __ia64_swab32(v);
        return v;
}

static inline UINT16
bswap16(UINT16 v)
{
        if(elf_is_big_endian) v = __ia64_swab16(v);
        return v;
}

static INTN
is_valid_header(Elf64_Ehdr *ehdr)
{
	UINT16 type, machine;

        if (ehdr->e_ident[EI_DATA] == ELFDATA2MSB) {
		type    = __ia64_swab16(ehdr->e_type);
		machine = __ia64_swab16(ehdr->e_machine);
	} else {
		type    = ehdr->e_type;
		machine = ehdr->e_machine;
	}
	VERB_PRT(3, Print(L"class=%d type=%d data=%d machine=%d\n", 
		ehdr->e_ident[EI_CLASS],
		type,
		ehdr->e_ident[EI_DATA],
		machine));

	return    ehdr->e_ident[EI_MAG0]  == 0x7f 
	       && ehdr->e_ident[EI_MAG1]  == 'E'
	       && ehdr->e_ident[EI_MAG2]  == 'L'
	       && ehdr->e_ident[EI_MAG3]  == 'F'
	       && ehdr->e_ident[EI_CLASS] == ELFCLASS64 
	       && type                    == ET_EXEC	/* must be executable */
	       && machine                 == EM_IA_64 ? 0 : -1;
}

/*
 * will invalidate loadble segments which overlap with others
 */ 
void
check_overlap(int i)
{
	int j;
	unsigned long iend = chunks[i].addr + chunks[i].size;

	for(j=0; j < nchunks; j++) {
		if (j ==i) continue;
		if (chunks[i].addr >= chunks[j].addr && iend < (chunks[j].addr + chunks[j].size)) {
			DBG_PRT((L"%s : segment %d fully included in segment %d\n", LD_NAME, i, j));
			CHUNK_INVALIDATE(i); /* nullyify segment */
			break;
		}
	}
}

void
analyze_chunks(void)
{
	INTN i;

	for(i=0; i < nchunks; i++) {
		if (CHUNK_IS_VALID(i) && !CHUNK_IS_LOAD(i)) check_overlap(i);
	}
}


/*
 * The decompression code calls this function after decompressing the
 * first block of the object file.  The first block must contain all
 * the relevant header information.
 */
int
first_block (const char *buf, long blocksize)
{
	Elf64_Ehdr *elf;
	Elf64_Phdr *phdrs;
	UINTN total_size, pages;
	UINTN low_addr, max_addr;
	UINTN load_offset = 0;
	UINTN offs = 0;
	UINT16 phnum;
	UINTN paddr, memsz;
	INTN i;

	elf  = (Elf64_Ehdr *)buf;
	
	if (is_valid_header(elf) == -1) return -1;

	/* determine file endianess */
        elf_is_big_endian = elf->e_ident[EI_DATA] == ELFDATA2MSB ? 1 : 0;