1 #include <u.h>
2 #include <libc.h>
3 #include <bio.h>
4 #include "elf.h"
5 #include "dwarf.h"
6 
7 static int
8 readblock(int fd, DwarfBlock *b, ulong off, ulong len)
9 {
10 	b->data = malloc(len);
11 	if(b->data == nil)
12 		return -1;
13 	if(seek(fd, off, 0) < 0 || readn(fd, b->data, len) != len){
14 		free(b->data);
15 		b->data = nil;
16 		return -1;
17 	}
18 	b->len = len;
19 	return 0;
20 }
21 
22 static int
23 findsection(Elf *elf, char *name, ulong *off, ulong *len)
24 {
25 	ElfSect *s;
26 
27 	if((s = elfsection(elf, name)) == nil)
28 		return -1;
29 	*off = s->offset;
30 	*len = s->size;
31 	return s - elf->sect;
32 }
33 
34 static int
35 loadsection(Elf *elf, char *name, DwarfBlock *b)
36 {
37 	ulong off, len;
38 
39 	if(findsection(elf, name, &off, &len) < 0)
40 		return -1;
41 	return readblock(elf->fd, b, off, len);
42 }
43 
44 Dwarf*
45 dwarfopen(Elf *elf)
46 {
47 	Dwarf *d;
48 
49 	if(elf == nil){
50 		werrstr("nil elf passed to dwarfopen");
51 		return nil;
52 	}
53 
54 	d = mallocz(sizeof(Dwarf), 1);
55 	if(d == nil)
56 		return nil;
57 
58 	d->elf = elf;
59 	if(loadsection(elf, ".debug_abbrev", &d->abbrev) < 0
60 	|| loadsection(elf, ".debug_aranges", &d->aranges) < 0
61 	|| loadsection(elf, ".debug_line", &d->line) < 0
62 	|| loadsection(elf, ".debug_pubnames", &d->pubnames) < 0
63 	|| loadsection(elf, ".debug_info", &d->info) < 0)
64 		goto err;
65 	loadsection(elf, ".debug_frame", &d->frame);
66 	loadsection(elf, ".debug_ranges", &d->ranges);
67 	loadsection(elf, ".debug_str", &d->str);
68 
69 	/* make this a table once there are more */
70 	switch(d->elf->hdr.machine){
71 	case ElfMach386:
72 		d->reg = dwarf386regs;
73 		d->nreg = dwarf386nregs;
74 		break;
75 	default:
76 		werrstr("unsupported machine");
77 		goto err;
78 	}
79 
80 	return d;
81 
82 err:
83 	free(d->abbrev.data);
84 	free(d->aranges.data);
85 	free(d->frame.data);
86 	free(d->line.data);
87 	free(d->pubnames.data);
88 	free(d->ranges.data);
89 	free(d->str.data);
90 	free(d->info.data);
91 	free(d);
92 	return nil;
93 }
94 
95 void
96 dwarfclose(Dwarf *d)
97 {
98 	free(d->abbrev.data);
99 	free(d->aranges.data);
100 	free(d->frame.data);
101 	free(d->line.data);
102 	free(d->pubnames.data);
103 	free(d->ranges.data);
104 	free(d->str.data);
105 	free(d->info.data);
106 	free(d);
107 }