1 /*
2 * Copyright (C) 2006 The Android Open Source Project
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * * Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * * Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in
12 * the documentation and/or other materials provided with the
13 * distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
16 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
17 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
18 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
19 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
21 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
22 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
23 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
24 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
25 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 */
28
29 #include <sys/types.h>
30 #include <linux/elf.h>
31 #include <link.h>
32
33 /* Dynamic binaries get this from the dynamic linker (system/linker), which
34 * we don't pull in for static bins. We also don't have a list of so's to
35 * iterate over, since there's really only a single monolithic blob of
36 * code/data.
37 *
38 * All we need to do is to find where the executable is in memory, and grab the
39 * phdr and phnum from there.
40 */
41
42 /* ld provides this to us in the default link script */
43 extern void *__executable_start;
44
45 int
dl_iterate_phdr(int (* cb)(struct dl_phdr_info * info,size_t size,void * data),void * data)46 dl_iterate_phdr(int (*cb)(struct dl_phdr_info *info, size_t size, void *data),
47 void *data)
48 {
49 struct dl_phdr_info dl_info;
50 Elf32_Ehdr *ehdr = (Elf32_Ehdr *) &__executable_start;
51 Elf32_Phdr *phdr = (Elf32_Phdr *)((unsigned long)ehdr + ehdr->e_phoff);
52
53 /* TODO: again, copied from linker.c. Find a better home for this
54 * later. */
55 if (ehdr->e_ident[EI_MAG0] != ELFMAG0) return -1;
56 if (ehdr->e_ident[EI_MAG1] != ELFMAG1) return -1;
57 if (ehdr->e_ident[EI_MAG2] != ELFMAG2) return -1;
58 if (ehdr->e_ident[EI_MAG3] != ELFMAG3) return -1;
59
60 dl_info.dlpi_addr = 0;
61 dl_info.dlpi_name = NULL;
62 dl_info.dlpi_phdr = phdr;
63 dl_info.dlpi_phnum = ehdr->e_phnum;
64 return cb(&dl_info, sizeof (struct dl_phdr_info), data);
65 }
66