/* * 8obj.c - identify and parse a 386 object file */#include <lib9.h>#include <bio.h>#include "8c/8.out.h"#include "obj.h" typedef struct Addr	Addr;struct Addr{	char	sym;	char	flags;};static	Addr	addr(Biobuf*);static	char	type2char(int);static	void	skip(Biobuf*, int); int_is8(char *t){	uchar *s = (uchar*)t; 	return  s[0] == (ANAME&0xff)			/* aslo = ANAME */		&& s[1] == ((ANAME>>8)&0xff)		&& s[2] == D_FILE			/* type */		&& s[3] == 1				/* sym */		&& s[4] == '<';				/* name of file */} int_read8(Biobuf *bp, Prog* p){	int as, n, c;	Addr a; 	as = Bgetc(bp);		/* as(low) */	if(as < 0)		return 0;	c = Bgetc(bp);		/* as(high) */	if(c < 0)		return 0;	as |= ((c & 0xff) << 8);	p->kind = aNone;	if(as == ANAME || as == ASIGNAME){		if(as == ASIGNAME)			skip(bp, 4);	/* signature */		p->kind = aName;		p->type = type2char(Bgetc(bp));		/* type */		p->sym = Bgetc(bp);			/* sym */		n = 0;		for(;;) {			as = Bgetc(bp);			if(as < 0)				return 0;			n++;			if(as == 0)				break;		}		p->id = malloc(n);		if(p->id == 0)			return 0;		Bseek(bp, -n, 1);		if(Bread(bp, p->id, n) != n)			return 0;		return 1;	}	if(as == ATEXT)		p->kind = aText;	if(as == AGLOBL)		p->kind = aData;	skip(bp, 4);		/* lineno(4) */	a = addr(bp);	addr(bp);	if(!(a.flags & T_SYM))		p->kind = aNone;	p->sym = a.sym;	return 1;} static Addraddr(Biobuf *bp){	Addr a;	int t;	long off; 	off = 0;	a.sym = -1;	a.flags = Bgetc(bp);			/* flags */	if(a.flags & T_INDEX)		skip(bp, 2);	if(a.flags & T_OFFSET){		off = Bgetc(bp);		off |= Bgetc(bp) << 8;		off |= Bgetc(bp) << 16;		off |= Bgetc(bp) << 24;		if(off < 0)			off = -off;	}	if(a.flags & T_SYM)		a.sym = Bgetc(bp);	if(a.flags & T_FCONST)		skip(bp, 8);	else	if(a.flags & T_SCONST)		skip(bp, NSNAME);	if(a.flags & T_TYPE) {		t = Bgetc(bp);		if(a.sym > 0 && (t==D_PARAM || t==D_AUTO))			_offset(a.sym, off);	}	return a;} static chartype2char(int t){	switch(t){	case D_EXTERN:		return 'U';	case D_STATIC:		return 'b';	case D_AUTO:		return 'a';	case D_PARAM:		return 'p';	default:		return UNKNOWN;	}} static voidskip(Biobuf *bp, int n){	while (n-- > 0)		Bgetc(bp);}