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284 lines
9.4 KiB
284 lines
9.4 KiB
/*
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* Copyright (C) 2017 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 <gtest/gtest.h>
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#include <dlfcn.h>
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#include <link.h>
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#if __has_include(<sys/auxv.h>)
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#include <sys/auxv.h>
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#endif
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#include <string>
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#include <unordered_map>
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TEST(link, dl_iterate_phdr_early_exit) {
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static size_t call_count = 0;
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ASSERT_EQ(123, dl_iterate_phdr([](dl_phdr_info*, size_t, void*) { ++call_count; return 123; },
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nullptr));
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ASSERT_EQ(1u, call_count);
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}
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TEST(link, dl_iterate_phdr) {
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struct Functor {
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static int Callback(dl_phdr_info* i, size_t s, void* data) {
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static_cast<Functor*>(data)->DoChecks(i, s);
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return 0;
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}
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void DoChecks(dl_phdr_info* info, size_t s) {
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ASSERT_EQ(sizeof(dl_phdr_info), s);
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ASSERT_TRUE(info->dlpi_name != nullptr);
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// An ELF file must have at least a PT_LOAD program header.
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ASSERT_NE(nullptr, info->dlpi_phdr);
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ASSERT_NE(0, info->dlpi_phnum);
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// Find the first PT_LOAD program header so we can find the ELF header.
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bool found_load = false;
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for (ElfW(Half) i = 0; i < info->dlpi_phnum; ++i) {
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const ElfW(Phdr)* phdr = reinterpret_cast<const ElfW(Phdr)*>(&info->dlpi_phdr[i]);
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if (phdr->p_type == PT_LOAD) {
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const ElfW(Ehdr)* ehdr = reinterpret_cast<const ElfW(Ehdr)*>(info->dlpi_addr +
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phdr->p_vaddr);
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// Does it look like an ELF file?
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ASSERT_EQ(0, memcmp(ehdr, ELFMAG, SELFMAG));
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// Does the e_phnum match what dl_iterate_phdr told us?
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ASSERT_EQ(info->dlpi_phnum, ehdr->e_phnum);
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found_load = true;
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break;
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}
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}
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ASSERT_EQ(true, found_load);
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}
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size_t count;
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} f = {};
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ASSERT_EQ(0, dl_iterate_phdr(Functor::Callback, &f));
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}
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// Verify that the module load/unload counters from dl_iterate_phdr are incremented.
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TEST(link, dl_iterate_phdr_counters) {
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struct Counters {
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bool inited = false;
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uint64_t adds = 0;
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uint64_t subs = 0;
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};
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auto get_adds_subs = []() {
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auto callback = [](dl_phdr_info* info, size_t size, void* data) {
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Counters& counters = *static_cast<Counters*>(data);
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EXPECT_GE(size, sizeof(dl_phdr_info));
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if (!counters.inited) {
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counters.inited = true;
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counters.adds = info->dlpi_adds;
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counters.subs = info->dlpi_subs;
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} else {
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// The counters have the same value for each module.
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EXPECT_EQ(counters.adds, info->dlpi_adds);
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EXPECT_EQ(counters.subs, info->dlpi_subs);
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}
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return 0;
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};
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Counters counters {};
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EXPECT_EQ(0, dl_iterate_phdr(callback, &counters));
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EXPECT_TRUE(counters.inited);
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return counters;
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};
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// dlopen increments the 'adds' counter.
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const auto before_dlopen = get_adds_subs();
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void* const handle = dlopen("libtest_empty.so", RTLD_NOW);
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ASSERT_NE(nullptr, handle);
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const auto after_dlopen = get_adds_subs();
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ASSERT_LT(before_dlopen.adds, after_dlopen.adds);
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ASSERT_EQ(before_dlopen.subs, after_dlopen.subs);
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// dlclose increments the 'subs' counter.
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const auto before_dlclose = after_dlopen;
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dlclose(handle);
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const auto after_dlclose = get_adds_subs();
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ASSERT_EQ(before_dlclose.adds, after_dlclose.adds);
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ASSERT_LT(before_dlclose.subs, after_dlclose.subs);
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}
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struct ProgHdr {
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const ElfW(Phdr)* table;
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size_t size;
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};
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__attribute__((__unused__))
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static ElfW(Addr) find_exe_load_bias(const ProgHdr& phdr) {
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for (size_t i = 0; i < phdr.size; ++i) {
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if (phdr.table[i].p_type == PT_PHDR) {
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return reinterpret_cast<ElfW(Addr)>(phdr.table) - phdr.table[i].p_vaddr;
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}
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}
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return 0;
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}
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__attribute__((__unused__))
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static ElfW(Dyn)* find_dynamic(const ProgHdr& phdr, ElfW(Addr) load_bias) {
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for (size_t i = 0; i < phdr.size; ++i) {
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if (phdr.table[i].p_type == PT_DYNAMIC) {
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return reinterpret_cast<ElfW(Dyn)*>(phdr.table[i].p_vaddr + load_bias);
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}
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}
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return nullptr;
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}
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__attribute__((__unused__))
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static r_debug* find_exe_r_debug(ElfW(Dyn)* dynamic) {
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for (ElfW(Dyn)* d = dynamic; d->d_tag != DT_NULL; ++d) {
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if (d->d_tag == DT_DEBUG) {
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return reinterpret_cast<r_debug*>(d->d_un.d_val);
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}
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}
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return nullptr;
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}
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// Walk the DT_DEBUG/_r_debug global module list and compare it with the same
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// information from dl_iterate_phdr. Verify that the executable appears first
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// in _r_debug.
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TEST(link, r_debug) {
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#if __has_include(<sys/auxv.h>)
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// Find the executable's PT_DYNAMIC segment and DT_DEBUG value. The linker
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// will write the address of its _r_debug global into the .dynamic section.
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ProgHdr exe_phdr = {
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.table = reinterpret_cast<ElfW(Phdr)*>(getauxval(AT_PHDR)),
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.size = getauxval(AT_PHNUM)
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};
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ASSERT_NE(nullptr, exe_phdr.table);
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ElfW(Addr) exe_load_bias = find_exe_load_bias(exe_phdr);
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ASSERT_NE(0u, exe_load_bias);
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ElfW(Dyn)* exe_dynamic = find_dynamic(exe_phdr, exe_load_bias);
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ASSERT_NE(nullptr, exe_dynamic);
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r_debug* dbg = find_exe_r_debug(exe_dynamic);
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ASSERT_NE(nullptr, dbg);
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// Use dl_iterate_phdr to build a table mapping from load bias values to
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// solib names and PT_DYNAMIC segments.
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struct DlIterateInfo {
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std::string name;
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ElfW(Dyn)* dynamic;
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};
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struct Functor {
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std::unordered_map<ElfW(Addr), DlIterateInfo> dl_iter_mods;
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static int Callback(dl_phdr_info* i, size_t s, void* data) {
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static_cast<Functor*>(data)->AddModule(i, s);
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return 0;
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}
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void AddModule(dl_phdr_info* info, size_t s) {
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ASSERT_EQ(sizeof(dl_phdr_info), s);
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ASSERT_TRUE(dl_iter_mods.find(info->dlpi_addr) == dl_iter_mods.end());
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ASSERT_TRUE(info->dlpi_name != nullptr);
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dl_iter_mods[info->dlpi_addr] = {
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.name = info->dlpi_name,
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.dynamic = find_dynamic({ info->dlpi_phdr, info->dlpi_phnum }, info->dlpi_addr)
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};
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}
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} f = {};
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ASSERT_EQ(0, dl_iterate_phdr(Functor::Callback, &f));
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size_t map_size = 0;
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for (link_map* map = dbg->r_map; map != nullptr; map = map->l_next) {
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ASSERT_NE(0u, map->l_addr);
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ASSERT_NE(nullptr, map->l_ld);
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ASSERT_NE(nullptr, map->l_name);
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auto it = f.dl_iter_mods.find(map->l_addr);
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ASSERT_TRUE(it != f.dl_iter_mods.end());
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const DlIterateInfo& info = it->second;
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ASSERT_EQ(info.name, map->l_name);
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ASSERT_EQ(info.dynamic, map->l_ld);
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++map_size;
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}
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// _r_debug and dl_iterate_phdr should report the same set of modules. We
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// verified above that every _r_debug module was reported by dl_iterate_phdr,
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// so checking the sizes verifies the converse.
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ASSERT_EQ(f.dl_iter_mods.size(), map_size);
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// Make sure the first entry is the executable. gdbserver assumes this and
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// removes the first entry from its list of shared objects that it sends back
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// to gdb.
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ASSERT_EQ(exe_load_bias, dbg->r_map->l_addr);
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ASSERT_EQ(exe_dynamic, dbg->r_map->l_ld);
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#endif
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}
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#if __arm__
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static uintptr_t read_exidx_func(uintptr_t* entry) {
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int32_t offset = *entry;
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// Sign-extend from int31 to int32.
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if ((offset & 0x40000000) != 0) {
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offset += -0x7fffffff - 1;
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}
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return reinterpret_cast<uintptr_t>(entry) + offset;
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}
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__attribute__((__unused__)) static void another_function_in_same_ELF_file() {}
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#endif
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TEST(link, dl_unwind_find_exidx) {
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#if __arm__
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int count = 0;
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struct eit_entry_t {
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uintptr_t one;
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uintptr_t two;
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};
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eit_entry_t* entries = reinterpret_cast<eit_entry_t*>(dl_unwind_find_exidx(
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reinterpret_cast<_Unwind_Ptr>(read_exidx_func), &count));
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ASSERT_TRUE(entries != nullptr);
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ASSERT_GT(count, 0);
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// Validity checks.
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uintptr_t func = reinterpret_cast<uintptr_t>(read_exidx_func);
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bool found = false;
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for (int i = 0; i < count; ++i) {
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// Entries must have bit 31 clear.
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ASSERT_TRUE((entries[i].one & (1<<31)) == 0);
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uintptr_t exidx_func = read_exidx_func(&entries[i].one);
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// If our function is compiled for thumb, exception table contains our address - 1.
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if (func == exidx_func || func == exidx_func + 1) found = true;
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// Entries must be sorted. Some addresses may appear twice if function
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// is compiled for arm.
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if (i > 0) {
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EXPECT_GE(exidx_func, read_exidx_func(&entries[i - 1].one)) << i;
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}
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}
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ASSERT_TRUE(found);
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#else
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GTEST_SKIP() << "dl_unwind_find_exidx is an ARM-only API";
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#endif
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}
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