a2e83ab348
Previously, Bionic's dl_phdr_info only included the first four
dl_iterate_phdr fields. Several other libc's have these additional fields:
unsigned long long dlpi_adds -- incremented when a library is loaded
unsigned long long dlpi_subs -- incremented when a library is unloaded
size_t dlpi_tls_modid -- TLS module ID
void* dlpi_tls_data -- pointer to current thread's TLS block or NULL
These extra fields are also exposed by glibc, musl, and FreeBSD. The
unwinder in libgcc.a, linked into shipping Android DSOs, has a
PC->eh_frame cache that activates if dl_phdr_info has the dlpi_adds and
dlpi_subs fields (indicated at run-time by a sufficiently-large size
argument to the callback).
Bug: https://github.com/android-ndk/ndk/issues/1062
Test: bionic unit tests
Change-Id: I6f0bab548cf8c828af2ddab9eb01c5c6d70cd81f
104 lines
4 KiB
C++
104 lines
4 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 <string.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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#include "private/bionic_elf_tls.h"
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#include "private/bionic_globals.h"
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#include "pthread_internal.h"
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/* ld provides this to us in the default link script */
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extern "C" 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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ElfW(Ehdr)* ehdr = reinterpret_cast<ElfW(Ehdr)*>(&__executable_start);
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if (memcmp(ehdr->e_ident, ELFMAG, SELFMAG) != 0) {
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return -1;
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}
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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 = reinterpret_cast<ElfW(Phdr)*>(reinterpret_cast<uintptr_t>(ehdr) + ehdr->e_phoff);
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exe_info.dlpi_phnum = ehdr->e_phnum;
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exe_info.dlpi_adds = 0;
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exe_info.dlpi_subs = 0;
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const TlsModules& tls_modules = __libc_shared_globals()->tls_modules;
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if (tls_modules.module_count == 0) {
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exe_info.dlpi_tls_modid = 0;
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exe_info.dlpi_tls_data = nullptr;
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} else {
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const size_t kExeModuleId = 1;
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const StaticTlsLayout& layout = __libc_shared_globals()->static_tls_layout;
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const TlsModule& tls_module = tls_modules.module_table[__tls_module_id_to_idx(kExeModuleId)];
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char* static_tls = reinterpret_cast<char*>(__get_bionic_tcb()) - layout.offset_bionic_tcb();
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exe_info.dlpi_tls_modid = kExeModuleId;
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exe_info.dlpi_tls_data = static_tls + tls_module.static_offset;
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}
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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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ElfW(Ehdr)* ehdr_vdso = reinterpret_cast<ElfW(Ehdr)*>(getauxval(AT_SYSINFO_EHDR));
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if (ehdr_vdso == nullptr) {
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// There is no VDSO, so there's nowhere left to look.
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return rc;
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}
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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 = reinterpret_cast<ElfW(Phdr)*>(reinterpret_cast<char*>(ehdr_vdso) + ehdr_vdso->e_phoff);
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vdso_info.dlpi_phnum = ehdr_vdso->e_phnum;
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vdso_info.dlpi_adds = 0;
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vdso_info.dlpi_subs = 0;
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vdso_info.dlpi_tls_modid = 0;
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vdso_info.dlpi_tls_data = nullptr;
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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 = (ElfW(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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}
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