148 lines
2.4 KiB
C
148 lines
2.4 KiB
C
/*
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* 6obj.c - identify and parse an amd64 object file
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*/
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#include <u.h>
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#include <libc.h>
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#include <bio.h>
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#include <mach.h>
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#include "6c/6.out.h"
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#include "obj.h"
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typedef struct Addr Addr;
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struct Addr
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{
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char sym;
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char flags;
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};
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static Addr addr(Biobuf*);
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static char type2char(int);
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static void skip(Biobuf*, int);
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int
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_is6(char *t)
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{
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uchar *s = (uchar*)t;
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return s[0] == (ANAME&0xff) /* aslo = ANAME */
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&& s[1] == ((ANAME>>8)&0xff)
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&& s[2] == D_FILE /* type */
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&& s[3] == 1 /* sym */
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&& s[4] == '<'; /* name of file */
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}
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int
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_read6(Biobuf *bp, Prog* p)
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{
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int as, n, c;
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Addr a;
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as = Bgetc(bp); /* as(low) */
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if(as < 0)
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return 0;
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c = Bgetc(bp); /* as(high) */
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if(c < 0)
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return 0;
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as |= ((c & 0xff) << 8);
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p->kind = aNone;
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p->sig = 0;
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if(as == ANAME || as == ASIGNAME){
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if(as == ASIGNAME){
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Bread(bp, &p->sig, 4);
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p->sig = leswal(p->sig);
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}
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p->kind = aName;
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p->type = type2char(Bgetc(bp)); /* type */
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p->sym = Bgetc(bp); /* sym */
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n = 0;
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for(;;) {
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as = Bgetc(bp);
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if(as < 0)
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return 0;
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n++;
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if(as == 0)
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break;
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}
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p->id = malloc(n);
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if(p->id == 0)
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return 0;
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Bseek(bp, -n, 1);
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if(Bread(bp, p->id, n) != n)
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return 0;
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return 1;
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}
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if(as == ATEXT)
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p->kind = aText;
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if(as == AGLOBL)
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p->kind = aData;
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skip(bp, 4); /* lineno(4) */
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a = addr(bp);
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addr(bp);
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if(!(a.flags & T_SYM))
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p->kind = aNone;
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p->sym = a.sym;
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return 1;
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}
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static Addr
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addr(Biobuf *bp)
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{
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Addr a;
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int t;
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long l;
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vlong off;
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off = 0;
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a.sym = -1;
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a.flags = Bgetc(bp); /* flags */
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if(a.flags & T_INDEX)
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skip(bp, 2);
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if(a.flags & T_OFFSET){
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l = Bgetc(bp);
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l |= Bgetc(bp) << 8;
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l |= Bgetc(bp) << 16;
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l |= Bgetc(bp) << 24;
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off = l;
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if(a.flags & T_64){
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l = Bgetc(bp);
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l |= Bgetc(bp) << 8;
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l |= Bgetc(bp) << 16;
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l |= Bgetc(bp) << 24;
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off = ((vlong)l << 32) | (off & 0xFFFFFFFF);
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}
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if(off < 0)
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off = -off;
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}
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if(a.flags & T_SYM)
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a.sym = Bgetc(bp);
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if(a.flags & T_FCONST)
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skip(bp, 8);
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else
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if(a.flags & T_SCONST)
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skip(bp, NSNAME);
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if(a.flags & T_TYPE) {
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t = Bgetc(bp);
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if(a.sym > 0 && (t==D_PARAM || t==D_AUTO))
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_offset(a.sym, off);
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}
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return a;
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}
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static char
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type2char(int t)
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{
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switch(t){
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case D_EXTERN: return 'U';
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case D_STATIC: return 'b';
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case D_AUTO: return 'a';
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case D_PARAM: return 'p';
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default: return UNKNOWN;
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}
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}
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static void
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skip(Biobuf *bp, int n)
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{
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while (n-- > 0)
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Bgetc(bp);
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}
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