1 /*
2 * 8obj.c - identify and parse a 386 object file
3 */
4 #include <lib9.h>
5 #include <bio.h>
6 #include "mach.h"
7 #include "8c/8.out.h"
8 #include "obj.h"
9
10 typedef struct Addr Addr;
11 struct Addr
12 {
13 char sym;
14 char flags;
15 };
16 static Addr addr(Biobuf*);
17 static char type2char(int);
18 static void skip(Biobuf*, int);
19
20 int
_is8(char * t)21 _is8(char *t)
22 {
23 uchar *s = (uchar*)t;
24
25 return s[0] == (ANAME&0xff) /* aslo = ANAME */
26 && s[1] == ((ANAME>>8)&0xff)
27 && s[2] == D_FILE /* type */
28 && s[3] == 1 /* sym */
29 && s[4] == '<'; /* name of file */
30 }
31
32 int
_read8(Biobuf * bp,Prog * p)33 _read8(Biobuf *bp, Prog* p)
34 {
35 int as, n, c;
36 Addr a;
37
38 as = Bgetc(bp); /* as(low) */
39 if(as < 0)
40 return 0;
41 c = Bgetc(bp); /* as(high) */
42 if(c < 0)
43 return 0;
44 as |= ((c & 0xff) << 8);
45 p->kind = aNone;
46 p->sig = 0;
47 if(as == ANAME || as == ASIGNAME){
48 if(as == ASIGNAME){
49 Bread(bp, &p->sig, 4);
50 p->sig = leswal(p->sig);
51 }
52 p->kind = aName;
53 p->type = type2char(Bgetc(bp)); /* type */
54 p->sym = Bgetc(bp); /* sym */
55 n = 0;
56 for(;;) {
57 as = Bgetc(bp);
58 if(as < 0)
59 return 0;
60 n++;
61 if(as == 0)
62 break;
63 }
64 p->id = malloc(n);
65 if(p->id == 0)
66 return 0;
67 Bseek(bp, -n, 1);
68 if(Bread(bp, p->id, n) != n)
69 return 0;
70 return 1;
71 }
72 if(as == ATEXT)
73 p->kind = aText;
74 if(as == AGLOBL)
75 p->kind = aData;
76 skip(bp, 4); /* lineno(4) */
77 a = addr(bp);
78 addr(bp);
79 if(!(a.flags & T_SYM))
80 p->kind = aNone;
81 p->sym = a.sym;
82 return 1;
83 }
84
85 static Addr
addr(Biobuf * bp)86 addr(Biobuf *bp)
87 {
88 Addr a;
89 int t;
90 long off;
91
92 off = 0;
93 a.sym = -1;
94 a.flags = Bgetc(bp); /* flags */
95 if(a.flags & T_INDEX)
96 skip(bp, 2);
97 if(a.flags & T_OFFSET){
98 off = Bgetc(bp);
99 off |= Bgetc(bp) << 8;
100 off |= Bgetc(bp) << 16;
101 off |= Bgetc(bp) << 24;
102 if(off < 0)
103 off = -off;
104 }
105 if(a.flags & T_SYM)
106 a.sym = Bgetc(bp);
107 if(a.flags & T_FCONST)
108 skip(bp, 8);
109 else
110 if(a.flags & T_SCONST)
111 skip(bp, NSNAME);
112 if(a.flags & T_TYPE) {
113 t = Bgetc(bp);
114 if(a.sym > 0 && (t==D_PARAM || t==D_AUTO))
115 _offset(a.sym, off);
116 }
117 return a;
118 }
119
120 static char
type2char(int t)121 type2char(int t)
122 {
123 switch(t){
124 case D_EXTERN: return 'U';
125 case D_STATIC: return 'b';
126 case D_AUTO: return 'a';
127 case D_PARAM: return 'p';
128 default: return UNKNOWN;
129 }
130 }
131
132 static void
skip(Biobuf * bp,int n)133 skip(Biobuf *bp, int n)
134 {
135 while (n-- > 0)
136 Bgetc(bp);
137 }
138