1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
|
/*
* Copyright © 2016 Intel Corporation
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
* and/or sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice (including the next
* paragraph) shall be included in all copies or substantial portions of the
* Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
* IN THE SOFTWARE.
*/
#ifdef HAVE_DL_ITERATE_PHDR
#include <dlfcn.h>
#include <link.h>
#include <stddef.h>
#include <string.h>
#include "build_id.h"
#ifndef NT_GNU_BUILD_ID
#define NT_GNU_BUILD_ID 3
#endif
#ifndef ElfW
#define ElfW(type) Elf_##type
#endif
#define ALIGN(val, align) (((val) + (align) - 1) & ~((align) - 1))
struct build_id_note {
ElfW(Nhdr) nhdr;
char name[4]; /* Note name for build-id is "GNU\0" */
uint8_t build_id[0];
};
struct callback_data {
/* Base address of shared object, taken from Dl_info::dli_fbase */
const void *dli_fbase;
struct build_id_note *note;
};
static int
build_id_find_nhdr_callback(struct dl_phdr_info *info, size_t size, void *data_)
{
struct callback_data *data = data_;
/* Calculate address where shared object is mapped into the process space.
* (Using the base address and the virtual address of the first LOAD segment)
*/
void *map_start = NULL;
for (unsigned i = 0; i < info->dlpi_phnum; i++) {
if (info->dlpi_phdr[i].p_type == PT_LOAD) {
map_start = (void *)(info->dlpi_addr + info->dlpi_phdr[i].p_vaddr);
break;
}
}
if (map_start != data->dli_fbase)
return 0;
for (unsigned i = 0; i < info->dlpi_phnum; i++) {
if (info->dlpi_phdr[i].p_type != PT_NOTE)
continue;
struct build_id_note *note = (void *)(info->dlpi_addr +
info->dlpi_phdr[i].p_vaddr);
ptrdiff_t len = info->dlpi_phdr[i].p_filesz;
while (len >= sizeof(struct build_id_note)) {
if (note->nhdr.n_type == NT_GNU_BUILD_ID &&
note->nhdr.n_descsz != 0 &&
note->nhdr.n_namesz == 4 &&
memcmp(note->name, "GNU", 4) == 0) {
data->note = note;
return 1;
}
size_t offset = sizeof(ElfW(Nhdr)) +
ALIGN(note->nhdr.n_namesz, 4) +
ALIGN(note->nhdr.n_descsz, 4);
note = (struct build_id_note *)((char *)note + offset);
len -= offset;
}
}
return 0;
}
const struct build_id_note *
build_id_find_nhdr_for_addr(const void *addr)
{
Dl_info info;
if (!dladdr(addr, &info))
return NULL;
if (!info.dli_fbase)
return NULL;
struct callback_data data = {
.dli_fbase = info.dli_fbase,
.note = NULL,
};
if (!dl_iterate_phdr(build_id_find_nhdr_callback, &data))
return NULL;
return data.note;
}
unsigned
build_id_length(const struct build_id_note *note)
{
return note->nhdr.n_descsz;
}
const uint8_t *
build_id_data(const struct build_id_note *note)
{
return note->build_id;
}
#endif
|
