1 /*
2  * Dwarf address ranges parsing code.
3  */
4 
5 #include <u.h>
6 #include <libc.h>
7 #include <bio.h>
8 #include "elf.h"
9 #include "dwarf.h"
10 
11 int
12 dwarfaddrtounit(Dwarf *d, ulong addr, ulong *unit)
13 {
14 	DwarfBuf b;
15 	int segsize, i;
16 	ulong len, id, off, base, size;
17 	uchar *start, *end;
18 
19 	memset(&b, 0, sizeof b);
20 	b.d = d;
21 	b.p = d->aranges.data;
22 	b.ep = b.p + d->aranges.len;
23 
24 	while(b.p < b.ep){
25 		start = b.p;
26 		len = dwarfget4(&b);
27 		if((id = dwarfget2(&b)) != 2){
28 			if(b.p == nil){
29 			underflow:
30 				werrstr("buffer underflow reading address ranges header");
31 			}else
32 				werrstr("bad dwarf version 0x%lux in address ranges header", id);
33 			return -1;
34 		}
35 		off = dwarfget4(&b);
36 		b.addrsize = dwarfget1(&b);
37 		if(d->addrsize == 0)
38 			d->addrsize = b.addrsize;
39 		segsize = dwarfget1(&b);
40 		USED(segsize);	/* what am i supposed to do with this? */
41 		if(b.p == nil)
42 			goto underflow;
43 		if((i = (b.p-start) % (2*b.addrsize)) != 0)
44 			b.p += 2*b.addrsize - i;
45 		end = start+4+len;
46 		while(b.p!=nil && b.p<end){
47 			base = dwarfgetaddr(&b);
48 			size = dwarfgetaddr(&b);
49 			if(b.p == nil)
50 				goto underflow;
51 			if(base <= addr && addr < base+size){
52 				*unit = off;
53 				return 0;
54 			}
55 		}
56 		if(b.p == nil)
57 			goto underflow;
58 		b.p = end;
59 	}
60 	werrstr("address 0x%lux is not listed in dwarf debugging symbols", addr);
61 	return -1;
62 }