[ia32rtools.git] / tools / cmpmrg_text.c

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <linux/coff.h>
#include <assert.h>
#include <stdint.h>

#include "my_assert.h"

/* http://www.delorie.com/djgpp/doc/coff/ */

typedef struct {
  unsigned short f_magic;         /* magic number             */
  unsigned short f_nscns;         /* number of sections       */
  unsigned int   f_timdat;        /* time & date stamp        */
  unsigned int   f_symptr;        /* file pointer to symtab   */
  unsigned int   f_nsyms;         /* number of symtab entries */
  unsigned short f_opthdr;        /* sizeof(optional hdr)     */
  unsigned short f_flags;         /* flags                    */
} FILHDR;

typedef struct {
  unsigned short magic;          /* type of file                         */
  unsigned short vstamp;         /* version stamp                        */
  unsigned int   tsize;          /* text size in bytes, padded to FW bdry*/
  unsigned int   dsize;          /* initialized data    "  "             */
  unsigned int   bsize;          /* uninitialized data  "  "             */
  unsigned int   entry;          /* entry pt.                            */
  unsigned int   text_start;     /* base of text used for this file      */
  unsigned int   data_start;     /* base of data used for this file      */
} AOUTHDR;

typedef struct {
  char           s_name[8];  /* section name                     */
  unsigned int   s_paddr;    /* physical address, aliased s_nlib */
  unsigned int   s_vaddr;    /* virtual address                  */
  unsigned int   s_size;     /* section size                     */
  unsigned int   s_scnptr;   /* file ptr to raw data for section */
  unsigned int   s_relptr;   /* file ptr to relocation           */
  unsigned int   s_lnnoptr;  /* file ptr to line numbers         */
  unsigned short s_nreloc;   /* number of relocation entries     */
  unsigned short s_nlnno;    /* number of line number entries    */
  unsigned int   s_flags;    /* flags                            */
} SCNHDR;

typedef struct {
  unsigned int  r_vaddr;   /* address of relocation      */
  unsigned int  r_symndx;  /* symbol we're adjusting for */
  unsigned short r_type;    /* type of relocation         */
} __attribute__((packed)) RELOC;

typedef struct {
  union {
    char e_name[E_SYMNMLEN];
    struct {
      unsigned int e_zeroes;
      unsigned int e_offset;
    } e;
  } e;
  unsigned int e_value;
  short e_scnum;
  unsigned short e_type;
  unsigned char e_sclass;
  unsigned char e_numaux;
} __attribute__((packed)) SYMENT;

#define C_EXT 2

struct my_symtab {
  unsigned int addr;
  unsigned int fpos; // for patching
  char *name;
};

static int symt_cmp(const void *p1_, const void *p2_)
{
	const struct my_symtab *p1 = p1_, *p2 = p2_;
	return p1->addr - p2->addr;
}

void parse_headers(FILE *f, unsigned int *base_out,
	long *sect_ofs, uint8_t **sect_data, long *sect_sz,
	RELOC **relocs, long *reloc_cnt,
	struct my_symtab **symtab_out, long *sym_cnt)
{
	struct my_symtab *symt_o = NULL;
	char *stringtab = NULL;
	unsigned int base = 0;
	int text_scnum = 0;
	long filesize;
	char symname[9];
	long opthdr_pos;
	long reloc_size;
	FILHDR hdr;
	AOUTHDR opthdr;
	SCNHDR scnhdr;
	SYMENT syment;
	int i, s, val;
	int ret;
	
	ret = fseek(f, 0, SEEK_END);
	my_assert(ret, 0);

	filesize = ftell(f);

	ret = fseek(f, 0, SEEK_SET);
	my_assert(ret, 0);

	ret = fread(&hdr, 1, sizeof(hdr), f);
	my_assert(ret, sizeof(hdr));

	if (hdr.f_magic == 0x5a4d) // MZ
	{
		ret = fseek(f, 0x3c, SEEK_SET);
		my_assert(ret, 0);
		ret = fread(&val, 1, sizeof(val), f);
		my_assert(ret, sizeof(val));

		ret = fseek(f, val, SEEK_SET);
		my_assert(ret, 0);
		ret = fread(&val, 1, sizeof(val), f);
		my_assert(ret, sizeof(val));
		my_assert(val, 0x4550); // PE

		// should be COFF now
		ret = fread(&hdr, 1, sizeof(hdr), f);
		my_assert(ret, sizeof(hdr));
	}

	my_assert(hdr.f_magic, COFF_I386MAGIC);

	if (hdr.f_opthdr != 0)
	{
		opthdr_pos = ftell(f);

		if (hdr.f_opthdr < sizeof(opthdr))
			my_assert(1, 0);

		ret = fread(&opthdr, 1, sizeof(opthdr), f);
		my_assert(ret, sizeof(opthdr));
		my_assert(opthdr.magic, COFF_ZMAGIC);

		printf("text_start: %x\n", opthdr.text_start);

		if (hdr.f_opthdr > sizeof(opthdr)) {
			ret = fread(&base, 1, sizeof(base), f);
			my_assert(ret, sizeof(base));
			printf("base: %x\n", base);
		}
		ret = fseek(f, opthdr_pos + hdr.f_opthdr, SEEK_SET);
		my_assert(ret, 0);
	}

	// note: assuming first non-empty one is .text ..
	for (s = 0; s < hdr.f_nscns; s++) {
		ret = fread(&scnhdr, 1, sizeof(scnhdr), f);
		my_assert(ret, sizeof(scnhdr));

		if (scnhdr.s_size != 0) {
			text_scnum = s + 1;
			break;
		}
	}

	printf("f_nsyms:  %x\n", hdr.f_nsyms);
	printf("s_name:   '%s'\n", scnhdr.s_name);
	printf("s_vaddr:  %x\n", scnhdr.s_vaddr);
	printf("s_size:   %x\n", scnhdr.s_size);
	//printf("s_scnptr: %x\n", scnhdr.s_scnptr);
	printf("s_nreloc: %x\n", scnhdr.s_nreloc);
	printf("--\n");

	ret = fseek(f, scnhdr.s_scnptr, SEEK_SET);
	my_assert(ret, 0);

	*sect_data = malloc(scnhdr.s_size);
	my_assert_not(*sect_data, NULL);
	ret = fread(*sect_data, 1, scnhdr.s_size, f);
	my_assert(ret, scnhdr.s_size);

	*sect_ofs = scnhdr.s_scnptr;
	*sect_sz = scnhdr.s_size;

	// relocs
	ret = fseek(f, scnhdr.s_relptr, SEEK_SET);
	my_assert(ret, 0);

	reloc_size = scnhdr.s_nreloc * sizeof((*relocs)[0]);
	*relocs = malloc(reloc_size + 1);
	my_assert_not(*relocs, NULL);
	ret = fread(*relocs, 1, reloc_size, f);
	my_assert(ret, reloc_size);

	*reloc_cnt = scnhdr.s_nreloc;

	// symtab
	if (hdr.f_nsyms != 0) {
		symname[8] = 0;

		symt_o = malloc(hdr.f_nsyms * sizeof(symt_o[0]) + 1);
		my_assert_not(symt_o, NULL);

		ret = fseek(f, hdr.f_symptr
				+ hdr.f_nsyms * sizeof(syment), SEEK_SET);
		my_assert(ret, 0);
		ret = fread(&i, 1, sizeof(i), f);
		my_assert(ret, sizeof(i));
		my_assert((unsigned int)i < filesize, 1);

		stringtab = malloc(i);
		my_assert_not(stringtab, NULL);
		memset(stringtab, 0, 4);
		ret = fread(stringtab + 4, 1, i - 4, f);
		my_assert(ret, i - 4);

		ret = fseek(f, hdr.f_symptr, SEEK_SET);
		my_assert(ret, 0);
	}

	for (i = s = 0; i < hdr.f_nsyms; i++) {
		long pos = ftell(f);

		ret = fread(&syment, 1, sizeof(syment), f);
		my_assert(ret, sizeof(syment));

		strncpy(symname, syment.e.e_name, 8);
		//printf("%3d %2d %08x '%s'\n", syment.e_sclass,
		//	syment.e_scnum, syment.e_value, symname);

		if (syment.e_scnum != text_scnum || syment.e_sclass != C_EXT)
			continue;

		symt_o[s].addr = syment.e_value;
		symt_o[s].fpos = pos;
		if (syment.e.e.e_zeroes == 0)
			symt_o[s].name = stringtab + syment.e.e.e_offset;
		else
			symt_o[s].name = strdup(symname);
		s++;

		if (syment.e_numaux) {
			ret = fseek(f, syment.e_numaux * sizeof(syment),
				    SEEK_CUR);
			my_assert(ret, 0);
			i += syment.e_numaux;
		}
	}

	if (symt_o != NULL)
		qsort(symt_o, s, sizeof(symt_o[0]), symt_cmp);

	*sym_cnt = s;
	*symtab_out = symt_o;

	if (base != 0 && base_out != NULL)
		*base_out = base + scnhdr.s_vaddr;
}

static int handle_pad(uint8_t *d_obj, uint8_t *d_exe, int maxlen)
{
	static const uint8_t p7[7] = { 0x8d, 0xa4, 0x24, 0x00, 0x00, 0x00, 0x00 };
	static const uint8_t p6[6] = { 0x8d, 0x9b, 0x00, 0x00, 0x00, 0x00 };
	static const uint8_t p5[5] = { 0x05, 0x00, 0x00, 0x00, 0x00 };
	static const uint8_t p4[4] = { 0x8d, 0x64, 0x24, 0x00 };
	static const uint8_t p3[3] = { 0x8d, 0x49, 0x00 };
	static const uint8_t p2[2] = { 0x8b, 0xff };
	static const uint8_t p1[1] = { 0x90 };
	int len;
	int i;

	for (i = 0; i < maxlen; i++)
		if (d_exe[i] != 0xcc)
			break;

	for (len = i; len > 0; )
	{
		i = len;
		if (i > 7)
			i = 7;

		switch (i) {
		#define CASE(x) \
		case sizeof(p ## x): \
			if (memcmp(d_obj, p ## x, sizeof(p ## x))) \
				return 0; \
			memset(d_obj, 0xcc, sizeof(p ## x)); \
			break;
		CASE(7)
		CASE(6)
		CASE(5)
		CASE(4)
		CASE(3)
		CASE(2)
		CASE(1)
		default:
			printf("%s: unhandled len: %d\n", __func__, len);
			return 0;
		#undef CASE
		}

		len -= i;
		d_obj += i;
	}

	return 1;
}

struct equiv_opcode {
	signed char len;
	signed char ofs;
	short cmp_rm;
	uint8_t v_masm[8];
	uint8_t v_masm_mask[8];
	uint8_t v_msvc[8];
	uint8_t v_msvc_mask[8];
} equiv_ops[] = {
	// cmp    $0x11,%ax
	{ 4, -1, 0,
	 { 0x66,0x83,0xf8,0x03 }, { 0xff,0xff,0xff,0x00 },
	 { 0x66,0x3d,0x03,0x00 }, { 0xff,0xff,0x00,0xff }, },
	// lea    -0x1(%ebx,%eax,1),%esi // op mod/rm sib offs
	// mov, test, imm grp 1
	{ 3, -2, 1,
	 { 0x8d,0x74,0x03 }, { 0xf0,0x07,0xc0 },
	 { 0x8d,0x74,0x18 }, { 0xf0,0x07,0xc0 }, },
	// movzbl 0x58f24a(%eax,%ecx,1),%eax
	{ 4, -3, 1,
	 { 0x0f,0xb6,0x84,0x08 }, { 0xff,0xff,0x07,0xc0 },
	 { 0x0f,0xb6,0x84,0x01 }, { 0xff,0xff,0x07,0xc0 }, },
	// inc/dec
	{ 3, -2, 1,
	 { 0xfe,0x4c,0x03 }, { 0xfe,0xff,0xc0 },
	 { 0xfe,0x4c,0x18 }, { 0xfe,0xff,0xc0 }, },
	// cmp
	{ 3, -2, 1,
	 { 0x38,0x0c,0x0c }, { 0xff,0xff,0xc0 },
	 { 0x38,0x0c,0x30 }, { 0xff,0xff,0xc0 }, },
	// test   %dl,%bl
	{ 2, -1, 1,
	 { 0x84,0xd3 }, { 0xfe,0xc0 },
	 { 0x84,0xda }, { 0xfe,0xc0 }, },
	// cmp	  r,r/m vs rm/r
	{ 2, 0, 1,
	 { 0x3a,0xca }, { 0xff,0xc0 },
	 { 0x38,0xd1 }, { 0xff,0xc0 }, },
	// rep + 66 prefix
	{ 2, 0, 0,
	 { 0xf3,0x66 }, { 0xfe,0xff },
	 { 0x66,0xf3 }, { 0xff,0xfe }, },
	// fadd   st, st(0) vs st(0), st
	{ 2, 0, 0,
	 { 0xd8,0xc0 }, { 0xff,0xf7 },
	 { 0xdc,0xc0 }, { 0xff,0xf7 }, },

	// broad filters (may take too much..)
	// testb  $0x4,0x1d(%esi,%eax,1)
	// movb, push, ..
	{ 3, -2, 1,
	 { 0xf6,0x44,0x06 }, { 0x00,0x07,0xc0 },
	 { 0xf6,0x44,0x30 }, { 0x00,0x07,0xc0 }, },
};

static int cmp_mask(uint8_t *d, uint8_t *expect, uint8_t *mask, int len)
{
	int i;

	for (i = 0; i < len; i++)
		if ((d[i] & mask[i]) != (expect[i] & mask[i]))
			return 1;

	return 0;
}

static int check_equiv(uint8_t *d_obj, uint8_t *d_exe, int maxlen)
{
	uint8_t vo, ve, vo2, ve2;
	int i, jo, je;
	int len, ofs;

	for (i = 0; i < sizeof(equiv_ops) / sizeof(equiv_ops[0]); i++)
	{
		struct equiv_opcode *op = &equiv_ops[i];

		len = op->len;
		if (maxlen < len)
			continue;

		ofs = op->ofs;
		if (cmp_mask(d_obj + ofs, op->v_masm,
			     op->v_masm_mask, len))
			continue;
		if (cmp_mask(d_exe + ofs, op->v_msvc,
			     op->v_msvc_mask, len))
			continue;

		jo = je = 0;
		d_obj += ofs;
		d_exe += ofs;
		while (1)
		{
			for (; jo < len; jo++)
				if (op->v_masm_mask[jo] != 0xff)
					break;
			for (; je < len; je++)
				if (op->v_msvc_mask[je] != 0xff)
					break;

			if ((jo == len && je != len) || (jo != len && je == len)) {
				printf("invalid equiv_ops\n");
				return -1;
			}
			if (jo == len)
				return len + ofs - 1; // matched

			// var byte
			vo = d_obj[jo] & ~op->v_masm_mask[jo];
			ve = d_exe[je] & ~op->v_msvc_mask[je];
			if (op->cmp_rm && op->v_masm_mask[jo] == 0xc0) {
				vo2 = vo >> 3;
				vo &= 7;
				ve2 = ve & 7;
				ve >>= 3;
				if (vo != ve || vo2 != ve2)
					return -1;
			}
			else {
				if (vo != ve)
					return -1;
			}

			jo++;
			je++;
		}
	}

	return -1;
}

int main(int argc, char *argv[])
{
	FILE *f_obj, *f_exe;
	long text_ofs_obj, text_ofs_exe;
	long sztext_obj, sztext_exe, sztext_cmn;
	RELOC *relocs_obj, *relocs_exe;
	long reloc_cnt_obj, reloc_cnt_exe;
	struct my_symtab *syms_obj, *syms_exe;
	long sym_cnt_obj, sym_cnt_exe;
	uint8_t *d_obj, *d_exe;
	unsigned int base = 0;
	int retval = 1;
	int left;
	int ret;
	int i;

	if (argc != 3) {
		printf("usage:\n%s <a_obj> <exe>\n", argv[0]);
		return 1;
	}

	f_obj = fopen(argv[1], "r+b");
	if (f_obj == NULL) {
		fprintf(stderr, "%s", argv[1]);
		perror("");
		return 1;
	}

	f_exe = fopen(argv[2], "r");
	if (f_exe == NULL) {
		fprintf(stderr, "%s", argv[2]);
		perror("");
		return 1;
	}

	parse_headers(f_obj, NULL, &text_ofs_obj, &d_obj, &sztext_obj,
		&relocs_obj, &reloc_cnt_obj, &syms_obj, &sym_cnt_obj);
	parse_headers(f_exe, &base, &text_ofs_exe, &d_exe, &sztext_exe,
		&relocs_exe, &reloc_cnt_exe, &syms_exe, &sym_cnt_exe);

	sztext_cmn = sztext_obj;
	if (sztext_cmn > sztext_exe)
		sztext_cmn = sztext_exe;

	if (sztext_cmn == 0) {
		printf("bad .text size(s): %ld, %ld\n",
			sztext_obj, sztext_exe);
		return 1;
	}

	for (i = 0; i < reloc_cnt_obj; i++)
	{
		unsigned int a = relocs_obj[i].r_vaddr;
		//printf("%04x %08x\n", relocs_obj[i].r_type, a);

		switch (relocs_obj[i].r_type) {
		case 0x06:
			memset(d_obj + a, 0, 4);
			memset(d_exe + a, 0, 4);
			break;
		default:
			printf("unknown reloc %x @%08x\n",
				relocs_obj[i].r_type, base + a);
			return 1;
		}
	}

	for (i = 0; i < sztext_cmn; i++)
	{
		if (d_obj[i] == d_exe[i])
			continue;

		left = sztext_cmn - i;

		if (d_exe[i] == 0xcc) { // padding
			if (handle_pad(d_obj + i, d_exe + i, left))
				continue;
		}

		ret = check_equiv(d_obj + i, d_exe + i, left);
		if (ret >= 0) {
			i += ret;
			continue;
		}

		printf("%x: %02x vs %02x\n", base + i, d_obj[i], d_exe[i]);
		goto out;
	}

out:
	return retval;
}
Commit	Line	Data
cfd23479	1	#include <stdio.h>
	2	#include <stdlib.h>
	3	#include <string.h>
	4	#include <linux/coff.h>
	5	#include <assert.h>
	6	#include <stdint.h>
	7
ede51255	8	#include "my_assert.h"
ede51255	9
cfd23479	10	/* http://www.delorie.com/djgpp/doc/coff/ */
	11
	12	typedef struct {
	13	unsigned short f_magic; /* magic number */
	14	unsigned short f_nscns; /* number of sections */
	15	unsigned int f_timdat; /* time & date stamp */
	16	unsigned int f_symptr; /* file pointer to symtab */
	17	unsigned int f_nsyms; /* number of symtab entries */
	18	unsigned short f_opthdr; /* sizeof(optional hdr) */
	19	unsigned short f_flags; /* flags */
	20	} FILHDR;
	21
	22	typedef struct {
	23	unsigned short magic; /* type of file */
	24	unsigned short vstamp; /* version stamp */
	25	unsigned int tsize; /* text size in bytes, padded to FW bdry*/
	26	unsigned int dsize; /* initialized data " " */
	27	unsigned int bsize; /* uninitialized data " " */
	28	unsigned int entry; /* entry pt. */
	29	unsigned int text_start; /* base of text used for this file */
	30	unsigned int data_start; /* base of data used for this file */
	31	} AOUTHDR;
	32
	33	typedef struct {
	34	char s_name[8]; /* section name */
	35	unsigned int s_paddr; /* physical address, aliased s_nlib */
	36	unsigned int s_vaddr; /* virtual address */
	37	unsigned int s_size; /* section size */
	38	unsigned int s_scnptr; /* file ptr to raw data for section */
	39	unsigned int s_relptr; /* file ptr to relocation */
	40	unsigned int s_lnnoptr; /* file ptr to line numbers */
	41	unsigned short s_nreloc; /* number of relocation entries */
	42	unsigned short s_nlnno; /* number of line number entries */
	43	unsigned int s_flags; /* flags */
	44	} SCNHDR;
	45
	46	typedef struct {
	47	unsigned int r_vaddr; /* address of relocation */
	48	unsigned int r_symndx; /* symbol we're adjusting for */
	49	unsigned short r_type; /* type of relocation */
	50	} __attribute__((packed)) RELOC;
	51
e86c9ee6	52	typedef struct {
	53	union {
	54	char e_name[E_SYMNMLEN];
	55	struct {
	56	unsigned int e_zeroes;
	57	unsigned int e_offset;
	58	} e;
	59	} e;
	60	unsigned int e_value;
	61	short e_scnum;
	62	unsigned short e_type;
	63	unsigned char e_sclass;
	64	unsigned char e_numaux;
	65	} __attribute__((packed)) SYMENT;
	66
	67	#define C_EXT 2
	68
	69	struct my_symtab {
	70	unsigned int addr;
	71	unsigned int fpos; // for patching
	72	char *name;
	73	};
	74
e86c9ee6	75	static int symt_cmp(const void p1_, const void p2_)
	76	{
	77	const struct my_symtab p1 = p1_, p2 = p2_;
	78	return p1->addr - p2->addr;
	79	}
	80
cfd23479	81	void parse_headers(FILE f, unsigned int base_out,
cfd23479	82	long sect_ofs, uint8_t sect_data, long sect_sz,
e86c9ee6	83	RELOC *relocs, long reloc_cnt,
e86c9ee6	84	struct my_symtab *symtab_out, long sym_cnt)
cfd23479	85	{
e86c9ee6	86	struct my_symtab *symt_o = NULL;
e86c9ee6	87	char *stringtab = NULL;
cfd23479	88	unsigned int base = 0;
e86c9ee6	89	int text_scnum = 0;
	90	long filesize;
	91	char symname[9];
cfd23479	92	long opthdr_pos;
	93	long reloc_size;
	94	FILHDR hdr;
	95	AOUTHDR opthdr;
	96	SCNHDR scnhdr;
e86c9ee6	97	SYMENT syment;
e86c9ee6	98	int i, s, val;
cfd23479	99	int ret;
cfd23479	100
e86c9ee6	101	ret = fseek(f, 0, SEEK_END);
	102	my_assert(ret, 0);
	103
	104	filesize = ftell(f);
	105
	106	ret = fseek(f, 0, SEEK_SET);
	107	my_assert(ret, 0);
	108
cfd23479	109	ret = fread(&hdr, 1, sizeof(hdr), f);
	110	my_assert(ret, sizeof(hdr));
	111
	112	if (hdr.f_magic == 0x5a4d) // MZ
	113	{
	114	ret = fseek(f, 0x3c, SEEK_SET);
	115	my_assert(ret, 0);
	116	ret = fread(&val, 1, sizeof(val), f);
	117	my_assert(ret, sizeof(val));
	118
	119	ret = fseek(f, val, SEEK_SET);
	120	my_assert(ret, 0);
	121	ret = fread(&val, 1, sizeof(val), f);
	122	my_assert(ret, sizeof(val));
	123	my_assert(val, 0x4550); // PE
	124
	125	// should be COFF now
	126	ret = fread(&hdr, 1, sizeof(hdr), f);
	127	my_assert(ret, sizeof(hdr));
	128	}
	129
	130	my_assert(hdr.f_magic, COFF_I386MAGIC);
	131
	132	if (hdr.f_opthdr != 0)
	133	{
	134	opthdr_pos = ftell(f);
	135
	136	if (hdr.f_opthdr < sizeof(opthdr))
	137	my_assert(1, 0);
	138
	139	ret = fread(&opthdr, 1, sizeof(opthdr), f);
	140	my_assert(ret, sizeof(opthdr));
	141	my_assert(opthdr.magic, COFF_ZMAGIC);
	142
	143	printf("text_start: %x\n", opthdr.text_start);
	144
	145	if (hdr.f_opthdr > sizeof(opthdr)) {
	146	ret = fread(&base, 1, sizeof(base), f);
	147	my_assert(ret, sizeof(base));
	148	printf("base: %x\n", base);
	149	}
	150	ret = fseek(f, opthdr_pos + hdr.f_opthdr, SEEK_SET);
	151	my_assert(ret, 0);
	152	}
	153
e86c9ee6	154	// note: assuming first non-empty one is .text ..
cfd23479	155	for (s = 0; s < hdr.f_nscns; s++) {
	156	ret = fread(&scnhdr, 1, sizeof(scnhdr), f);
	157	my_assert(ret, sizeof(scnhdr));
	158
e86c9ee6	159	if (scnhdr.s_size != 0) {
e86c9ee6	160	text_scnum = s + 1;
cfd23479	161	break;
e86c9ee6	162	}
cfd23479	163	}
cfd23479	164
e86c9ee6	165	printf("f_nsyms: %x\n", hdr.f_nsyms);
cfd23479	166	printf("s_name: '%s'\n", scnhdr.s_name);
	167	printf("s_vaddr: %x\n", scnhdr.s_vaddr);
	168	printf("s_size: %x\n", scnhdr.s_size);
e86c9ee6	169	//printf("s_scnptr: %x\n", scnhdr.s_scnptr);
cfd23479	170	printf("s_nreloc: %x\n", scnhdr.s_nreloc);
	171	printf("--\n");
	172
	173	ret = fseek(f, scnhdr.s_scnptr, SEEK_SET);
	174	my_assert(ret, 0);
	175
	176	*sect_data = malloc(scnhdr.s_size);
	177	my_assert_not(*sect_data, NULL);
	178	ret = fread(*sect_data, 1, scnhdr.s_size, f);
	179	my_assert(ret, scnhdr.s_size);
	180
	181	*sect_ofs = scnhdr.s_scnptr;
	182	*sect_sz = scnhdr.s_size;
	183
e86c9ee6	184	// relocs
cfd23479	185	ret = fseek(f, scnhdr.s_relptr, SEEK_SET);
	186	my_assert(ret, 0);
	187
	188	reloc_size = scnhdr.s_nreloc * sizeof((*relocs)[0]);
	189	*relocs = malloc(reloc_size + 1);
	190	my_assert_not(*relocs, NULL);
	191	ret = fread(*relocs, 1, reloc_size, f);
	192	my_assert(ret, reloc_size);
	193
	194	*reloc_cnt = scnhdr.s_nreloc;
	195
e86c9ee6	196	// symtab
	197	if (hdr.f_nsyms != 0) {
	198	symname[8] = 0;
	199
	200	symt_o = malloc(hdr.f_nsyms * sizeof(symt_o[0]) + 1);
	201	my_assert_not(symt_o, NULL);
	202
	203	ret = fseek(f, hdr.f_symptr
	204	+ hdr.f_nsyms * sizeof(syment), SEEK_SET);
	205	my_assert(ret, 0);
	206	ret = fread(&i, 1, sizeof(i), f);
	207	my_assert(ret, sizeof(i));
	208	my_assert((unsigned int)i < filesize, 1);
	209
	210	stringtab = malloc(i);
	211	my_assert_not(stringtab, NULL);
	212	memset(stringtab, 0, 4);
	213	ret = fread(stringtab + 4, 1, i - 4, f);
	214	my_assert(ret, i - 4);
	215
	216	ret = fseek(f, hdr.f_symptr, SEEK_SET);
	217	my_assert(ret, 0);
	218	}
	219
	220	for (i = s = 0; i < hdr.f_nsyms; i++) {
	221	long pos = ftell(f);
	222
	223	ret = fread(&syment, 1, sizeof(syment), f);
	224	my_assert(ret, sizeof(syment));
	225
	226	strncpy(symname, syment.e.e_name, 8);
	227	//printf("%3d %2d %08x '%s'\n", syment.e_sclass,
	228	// syment.e_scnum, syment.e_value, symname);
	229
	230	if (syment.e_scnum != text_scnum \|\| syment.e_sclass != C_EXT)
	231	continue;
	232
	233	symt_o[s].addr = syment.e_value;
	234	symt_o[s].fpos = pos;
	235	if (syment.e.e.e_zeroes == 0)
	236	symt_o[s].name = stringtab + syment.e.e.e_offset;
	237	else
	238	symt_o[s].name = strdup(symname);
	239	s++;
	240
	241	if (syment.e_numaux) {
	242	ret = fseek(f, syment.e_numaux * sizeof(syment),
	243	SEEK_CUR);
	244	my_assert(ret, 0);
	245	i += syment.e_numaux;
	246	}
	247	}
	248
	249	if (symt_o != NULL)
	250	qsort(symt_o, s, sizeof(symt_o[0]), symt_cmp);
	251
	252	*sym_cnt = s;
	253	*symtab_out = symt_o;
	254
	255	if (base != 0 && base_out != NULL)
cfd23479	256	*base_out = base + scnhdr.s_vaddr;
	257	}
	258
	259	static int handle_pad(uint8_t d_obj, uint8_t d_exe, int maxlen)
	260	{
	261	static const uint8_t p7[7] = { 0x8d, 0xa4, 0x24, 0x00, 0x00, 0x00, 0x00 };
	262	static const uint8_t p6[6] = { 0x8d, 0x9b, 0x00, 0x00, 0x00, 0x00 };
	263	static const uint8_t p5[5] = { 0x05, 0x00, 0x00, 0x00, 0x00 };
	264	static const uint8_t p4[4] = { 0x8d, 0x64, 0x24, 0x00 };
	265	static const uint8_t p3[3] = { 0x8d, 0x49, 0x00 };
	266	static const uint8_t p2[2] = { 0x8b, 0xff };
	267	static const uint8_t p1[1] = { 0x90 };
	268	int len;
	269	int i;
	270
	271	for (i = 0; i < maxlen; i++)
	272	if (d_exe[i] != 0xcc)
	273	break;
	274
	275	for (len = i; len > 0; )
	276	{
	277	i = len;
	278	if (i > 7)
	279	i = 7;
	280
	281	switch (i) {
	282	#define CASE(x) \
	283	case sizeof(p ## x): \
	284	if (memcmp(d_obj, p ## x, sizeof(p ## x))) \
	285	return 0; \
	286	memset(d_obj, 0xcc, sizeof(p ## x)); \
	287	break;
	288	CASE(7)
	289	CASE(6)
	290	CASE(5)
	291	CASE(4)
	292	CASE(3)
	293	CASE(2)
	294	CASE(1)
	295	default:
	296	printf("%s: unhandled len: %d\n", __func__, len);
	297	return 0;
	298	#undef CASE
	299	}
	300
	301	len -= i;
	302	d_obj += i;
	303	}
	304
	305	return 1;
	306	}
	307
	308	struct equiv_opcode {
	309	signed char len;
	310	signed char ofs;
	311	short cmp_rm;
	312	uint8_t v_masm[8];
	313	uint8_t v_masm_mask[8];
	314	uint8_t v_msvc[8];
	315	uint8_t v_msvc_mask[8];
	316	} equiv_ops[] = {
	317	// cmp $0x11,%ax
	318	{ 4, -1, 0,
	319	{ 0x66,0x83,0xf8,0x03 }, { 0xff,0xff,0xff,0x00 },
320	{ 0x66,0x3d,0x03,0x00 }, { 0xff,0xff,0x00,0xff }, },
321	// lea -0x1(%ebx,%eax,1),%esi // op mod/rm sib offs
322	// mov, test, imm grp 1
323	{ 3, -2, 1,
324	{ 0x8d,0x74,0x03 }, { 0xf0,0x07,0xc0 },
325	{ 0x8d,0x74,0x18 }, { 0xf0,0x07,0xc0 }, },
326	// movzbl 0x58f24a(%eax,%ecx,1),%eax
327	{ 4, -3, 1,
328	{ 0x0f,0xb6,0x84,0x08 }, { 0xff,0xff,0x07,0xc0 },
329	{ 0x0f,0xb6,0x84,0x01 }, { 0xff,0xff,0x07,0xc0 }, },
330	// inc/dec
331	{ 3, -2, 1,
332	{ 0xfe,0x4c,0x03 }, { 0xfe,0xff,0xc0 },
333	{ 0xfe,0x4c,0x18 }, { 0xfe,0xff,0xc0 }, },
334	// cmp
335	{ 3, -2, 1,
336	{ 0x38,0x0c,0x0c }, { 0xff,0xff,0xc0 },
337	{ 0x38,0x0c,0x30 }, { 0xff,0xff,0xc0 }, },
338	// test %dl,%bl
339	{ 2, -1, 1,
340	{ 0x84,0xd3 }, { 0xfe,0xc0 },
341	{ 0x84,0xda }, { 0xfe,0xc0 }, },
342	// cmp r,r/m vs rm/r
343	{ 2, 0, 1,
344	{ 0x3a,0xca }, { 0xff,0xc0 },
345	{ 0x38,0xd1 }, { 0xff,0xc0 }, },
346	// rep + 66 prefix
347	{ 2, 0, 0,
348	{ 0xf3,0x66 }, { 0xfe,0xff },
349	{ 0x66,0xf3 }, { 0xff,0xfe }, },
350	// fadd st, st(0) vs st(0), st
351	{ 2, 0, 0,
352	{ 0xd8,0xc0 }, { 0xff,0xf7 },
353	{ 0xdc,0xc0 }, { 0xff,0xf7 }, },
354
355	// broad filters (may take too much..)
356	// testb $0x4,0x1d(%esi,%eax,1)
357	// movb, push, ..
358	{ 3, -2, 1,
359	{ 0xf6,0x44,0x06 }, { 0x00,0x07,0xc0 },
360	{ 0xf6,0x44,0x30 }, { 0x00,0x07,0xc0 }, },
361	};
362
363	static int cmp_mask(uint8_t d, uint8_t expect, uint8_t *mask, int len)
364	{
365	int i;
366
367	for (i = 0; i < len; i++)
368	if ((d[i] & mask[i]) != (expect[i] & mask[i]))
369	return 1;
370
371	return 0;
372	}
373
374	static int check_equiv(uint8_t d_obj, uint8_t d_exe, int maxlen)
375	{
376	uint8_t vo, ve, vo2, ve2;
377	int i, jo, je;
378	int len, ofs;
379
380	for (i = 0; i < sizeof(equiv_ops) / sizeof(equiv_ops[0]); i++)
381	{
382	struct equiv_opcode *op = &equiv_ops[i];
383
384	len = op->len;
385	if (maxlen < len)
386	continue;
387
388	ofs = op->ofs;
389	if (cmp_mask(d_obj + ofs, op->v_masm,
390	op->v_masm_mask, len))
391	continue;
392	if (cmp_mask(d_exe + ofs, op->v_msvc,
393	op->v_msvc_mask, len))
394	continue;
395
396	jo = je = 0;
397	d_obj += ofs;
398	d_exe += ofs;
399	while (1)
400	{
401	for (; jo < len; jo++)
402	if (op->v_masm_mask[jo] != 0xff)
403	break;
404	for (; je < len; je++)
405	if (op->v_msvc_mask[je] != 0xff)
406	break;
407
408	if ((jo == len && je != len) \|\| (jo != len && je == len)) {
409	printf("invalid equiv_ops\n");
410	return -1;
411	}
412	if (jo == len)
413	return len + ofs - 1; // matched
414
415	// var byte
416	vo = d_obj[jo] & ~op->v_masm_mask[jo];
417	ve = d_exe[je] & ~op->v_msvc_mask[je];
418	if (op->cmp_rm && op->v_masm_mask[jo] == 0xc0) {
419	vo2 = vo >> 3;
420	vo &= 7;
421	ve2 = ve & 7;
422	ve >>= 3;
423	if (vo != ve \|\| vo2 != ve2)
424	return -1;
425	}
426	else {
427	if (vo != ve)
428	return -1;
429	}
430
431	jo++;
432	je++;
433	}
434	}
435
436	return -1;
437	}
438
439	int main(int argc, char *argv[])
440	{
441	FILE f_obj, f_exe;
442	long text_ofs_obj, text_ofs_exe;
443	long sztext_obj, sztext_exe, sztext_cmn;
444	RELOC relocs_obj, relocs_exe;
e86c9ee6	445	long reloc_cnt_obj, reloc_cnt_exe;
	446	struct my_symtab syms_obj, syms_exe;
	447	long sym_cnt_obj, sym_cnt_exe;
cfd23479	448	uint8_t d_obj, d_exe;
e86c9ee6	449	unsigned int base = 0;
cfd23479	450	int retval = 1;
	451	int left;
	452	int ret;
	453	int i;
	454
	455	if (argc != 3) {
e86c9ee6	456	printf("usage:\n%s <a_obj> <exe>\n", argv[0]);
cfd23479	457	return 1;
	458	}
	459
	460	f_obj = fopen(argv[1], "r+b");
	461	if (f_obj == NULL) {
	462	fprintf(stderr, "%s", argv[1]);
	463	perror("");
	464	return 1;
	465	}
	466
	467	f_exe = fopen(argv[2], "r");
	468	if (f_exe == NULL) {
e86c9ee6	469	fprintf(stderr, "%s", argv[2]);
cfd23479	470	perror("");
	471	return 1;
	472	}
	473
e86c9ee6	474	parse_headers(f_obj, NULL, &text_ofs_obj, &d_obj, &sztext_obj,
e86c9ee6	475	&relocs_obj, &reloc_cnt_obj, &syms_obj, &sym_cnt_obj);
cfd23479	476	parse_headers(f_exe, &base, &text_ofs_exe, &d_exe, &sztext_exe,
e86c9ee6	477	&relocs_exe, &reloc_cnt_exe, &syms_exe, &sym_cnt_exe);
cfd23479	478
	479	sztext_cmn = sztext_obj;
	480	if (sztext_cmn > sztext_exe)
	481	sztext_cmn = sztext_exe;
cfd23479	482
	483	if (sztext_cmn == 0) {
	484	printf("bad .text size(s): %ld, %ld\n",
	485	sztext_obj, sztext_exe);
	486	return 1;
	487	}
	488
e86c9ee6	489	for (i = 0; i < reloc_cnt_obj; i++)
cfd23479	490	{
	491	unsigned int a = relocs_obj[i].r_vaddr;
	492	//printf("%04x %08x\n", relocs_obj[i].r_type, a);
	493
	494	switch (relocs_obj[i].r_type) {
	495	case 0x06:
	496	memset(d_obj + a, 0, 4);
	497	memset(d_exe + a, 0, 4);
	498	break;
	499	default:
	500	printf("unknown reloc %x @%08x\n",
	501	relocs_obj[i].r_type, base + a);
	502	return 1;
	503	}
	504	}
	505
	506	for (i = 0; i < sztext_cmn; i++)
	507	{
	508	if (d_obj[i] == d_exe[i])
	509	continue;
	510
	511	left = sztext_cmn - i;
	512
	513	if (d_exe[i] == 0xcc) { // padding
	514	if (handle_pad(d_obj + i, d_exe + i, left))
	515	continue;
	516	}
	517
	518	ret = check_equiv(d_obj + i, d_exe + i, left);
	519	if (ret >= 0) {
	520	i += ret;
	521	continue;
	522	}
	523
	524	printf("%x: %02x vs %02x\n", base + i, d_obj[i], d_exe[i]);
	525	goto out;
	526	}
	527
	528	out:
	529	return retval;
	530	}