82 lines
3.3 KiB
C
82 lines
3.3 KiB
C
/*
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* Copyright (C) 2006 The Android Open Source Project
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* * Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* * Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
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* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include <elf.h>
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#include <sys/auxv.h>
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#include <sys/types.h>
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#include <link.h>
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/* ld provides this to us in the default link script */
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extern void* __executable_start;
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int dl_iterate_phdr(int (*cb)(struct dl_phdr_info* info, size_t size, void* data), void* data) {
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Elf_Ehdr* ehdr = (Elf_Ehdr*) &__executable_start;
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// TODO: again, copied from linker.c. Find a better home for this later.
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if (ehdr->e_ident[EI_MAG0] != ELFMAG0) return -1;
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if (ehdr->e_ident[EI_MAG1] != ELFMAG1) return -1;
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if (ehdr->e_ident[EI_MAG2] != ELFMAG2) return -1;
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if (ehdr->e_ident[EI_MAG3] != ELFMAG3) return -1;
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// Dynamic binaries get their dl_iterate_phdr from the dynamic linker, but
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// static binaries get this. We don't have a list of shared objects to
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// iterate over, since there's really only a single monolithic blob of
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// code/data, plus optionally a VDSO.
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struct dl_phdr_info exe_info;
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exe_info.dlpi_addr = 0;
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exe_info.dlpi_name = NULL;
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exe_info.dlpi_phdr = (Elf_Phdr*) ((unsigned long) ehdr + ehdr->e_phoff);
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exe_info.dlpi_phnum = ehdr->e_phnum;
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#ifdef AT_SYSINFO_EHDR
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// Try the executable first.
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int rc = cb(&exe_info, sizeof(exe_info), data);
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if (rc != 0) {
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return rc;
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}
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// Try the VDSO if that didn't work.
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Elf_Ehdr* ehdr_vdso = (Elf_Ehdr*) getauxval(AT_SYSINFO_EHDR);
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struct dl_phdr_info vdso_info;
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vdso_info.dlpi_addr = 0;
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vdso_info.dlpi_name = NULL;
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vdso_info.dlpi_phdr = (Elf_Phdr*) ((char*) ehdr_vdso + ehdr_vdso->e_phoff);
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vdso_info.dlpi_phnum = ehdr_vdso->e_phnum;
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for (size_t i = 0; i < vdso_info.dlpi_phnum; ++i) {
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if (vdso_info.dlpi_phdr[i].p_type == PT_LOAD) {
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vdso_info.dlpi_addr = (Elf_Addr) ehdr_vdso - vdso_info.dlpi_phdr[i].p_vaddr;
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break;
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}
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}
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return cb(&vdso_info, sizeof(vdso_info), data);
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#else
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// There's only the executable to try.
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return cb(&exe_info, sizeof(exe_info), data);
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#endif
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}
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