1 /* $OpenBSD: exidx.c,v 1.2 2016/09/18 00:19:37 jsg Exp $ */
2 /*
3 * Copyright (c) 2016 Mark Kettenis <kettenis@openbsd.org>
4 *
5 * Permission to use, copy, modify, and distribute this software for any
6 * purpose with or without fee is hereby granted, provided that the above
7 * copyright notice and this permission notice appear in all copies.
8 *
9 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
10 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
11 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
12 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
13 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
14 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
15 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
16 */
17
18 #include <sys/types.h>
19 #include <link.h>
20 #include <stddef.h>
21
22 void *dl_unwind_find_exidx(const void *pc, int *pcount) __attribute__((weak));
23
24 struct exidx_data {
25 u_long pc;
26 void *exidx;
27 int *pcount;
28 };
29
30 struct exidx_entry {
31 uint32_t data[2];
32 };
33
34 static int
find_exidx(struct dl_phdr_info * info,size_t size,void * p)35 find_exidx(struct dl_phdr_info *info, size_t size, void *p)
36 {
37 struct exidx_data *data = p;
38 const Elf_Phdr *phdr;
39 void *exidx;
40 int count = 0;
41 int found = 0;
42 int i;
43
44 for (i = 0; i < info->dlpi_phnum; i++) {
45 phdr = &info->dlpi_phdr[i];
46 if (data->pc >= info->dlpi_addr + phdr->p_vaddr &&
47 data->pc < info->dlpi_addr + phdr->p_vaddr + phdr->p_memsz)
48 found = 1;
49 if (phdr->p_type == PT_ARM_EXIDX) {
50 exidx = (void *)(info->dlpi_addr + phdr->p_vaddr);
51 count = phdr->p_memsz / sizeof(struct exidx_entry);
52 }
53 }
54
55 if (found && count > 0) {
56 data->exidx = exidx;
57 *data->pcount = count;
58 return 1;
59 }
60
61 return 0;
62 }
63
64 void *
dl_unwind_find_exidx(const void * pc,int * pcount)65 dl_unwind_find_exidx(const void *pc, int *pcount)
66 {
67 struct exidx_data data;
68
69 data.pc = (u_long)pc;
70 data.pcount = pcount;
71 if (dl_iterate_phdr(find_exidx, &data))
72 return data.exidx;
73 return NULL;
74 }
75
76 __strong_alias(__gnu_Unwind_Find_exidx, dl_unwind_find_exidx);
77