1/* bionic/arch-x86/bionic/dl_iterate_phdr_static.c
2**
3** Copyright 2006, The Android Open Source Project
4**
5** Redistribution and use in source and binary forms, with or without
6** modification, are permitted provided that the following conditions are met:
7**     * Redistributions of source code must retain the above copyright
8**       notice, this list of conditions and the following disclaimer.
9**     * Redistributions in binary form must reproduce the above copyright
10**       notice, this list of conditions and the following disclaimer in the
11**       documentation and/or other materials provided with the distribution.
12**     * Neither the name of Google Inc. nor the names of its contributors may
13**       be used to endorse or promote products derived from this software
14**       without specific prior written permission.
15**
16** THIS SOFTWARE IS PROVIDED BY Google Inc. ``AS IS'' AND ANY EXPRESS OR
17** IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
18** MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
19** EVENT SHALL Google Inc. BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
20** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
21** PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
22** OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
23** WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
24** OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
25** ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
26*/
27
28#include <sys/types.h>
29#include <linux/elf.h>
30
31/* TODO: Move this into a header that linker.h can also pull it in.
32 * Silly to have same struct in 2 places. This is temporary. */
33struct dl_phdr_info
34{
35    Elf32_Addr dlpi_addr;
36    const char *dlpi_name;
37    const Elf32_Phdr *dlpi_phdr;
38    Elf32_Half dlpi_phnum;
39};
40
41/* Dynamic binaries get this from the dynamic linker (system/linker), which
42 * we don't pull in for static bins. We also don't have a list of so's to
43 * iterate over, since there's really only a single monolithic blob of
44 * code/data.
45 *
46 * All we need to do is to find where the executable is in memory, and grab the
47 * phdr and phnum from there.
48 */
49
50/* ld provides this to us in the default link script */
51extern void *__executable_start;
52
53int
54dl_iterate_phdr(int (*cb)(struct dl_phdr_info *info, size_t size, void *data),
55                void *data)
56{
57    struct dl_phdr_info dl_info;
58    Elf32_Ehdr *ehdr = (Elf32_Ehdr *) &__executable_start;
59    Elf32_Phdr *phdr = (Elf32_Phdr *)((unsigned long)ehdr + ehdr->e_phoff);
60
61    /* TODO: again, copied from linker.c. Find a better home for this
62     * later. */
63    if (ehdr->e_ident[EI_MAG0] != ELFMAG0) return -1;
64    if (ehdr->e_ident[EI_MAG1] != ELFMAG1) return -1;
65    if (ehdr->e_ident[EI_MAG2] != ELFMAG2) return -1;
66    if (ehdr->e_ident[EI_MAG3] != ELFMAG3) return -1;
67
68    dl_info.dlpi_addr = 0;
69    dl_info.dlpi_name = NULL;
70    dl_info.dlpi_phdr = phdr;
71    dl_info.dlpi_phnum = ehdr->e_phnum;
72    return cb(&dl_info, sizeof (struct dl_phdr_info), data);
73}
74
75