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      1 /*
      2  * Copyright (C) 2017 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 <gtest/gtest.h>
     30 
     31 #include <link.h>
     32 
     33 TEST(link, dl_iterate_phdr_early_exit) {
     34   static size_t call_count = 0;
     35   ASSERT_EQ(123, dl_iterate_phdr([](dl_phdr_info*, size_t, void*) { ++call_count; return 123; },
     36                                  nullptr));
     37   ASSERT_EQ(1u, call_count);
     38 }
     39 
     40 TEST(link, dl_iterate_phdr) {
     41   struct Functor {
     42     static int Callback(dl_phdr_info* i, size_t s, void* data) {
     43       reinterpret_cast<Functor*>(data)->DoChecks(i, s);
     44       return 0;
     45     }
     46     void DoChecks(dl_phdr_info* info, size_t s) {
     47       ASSERT_EQ(sizeof(dl_phdr_info), s);
     48 
     49       ASSERT_TRUE(info->dlpi_name != nullptr);
     50 
     51       // Find the first PT_LOAD program header so we can find the ELF header.
     52       for (ElfW(Half) i = 0; i < info->dlpi_phnum; ++i) {
     53         const ElfW(Phdr)* phdr = reinterpret_cast<const ElfW(Phdr)*>(&info->dlpi_phdr[i]);
     54         if (phdr->p_type == PT_LOAD) {
     55           const ElfW(Ehdr)* ehdr = reinterpret_cast<const ElfW(Ehdr)*>(info->dlpi_addr +
     56                                                                        phdr->p_vaddr);
     57           // Does it look like an ELF file?
     58           ASSERT_EQ(0, memcmp(ehdr, ELFMAG, SELFMAG));
     59           // Does the e_phnum match what dl_iterate_phdr told us?
     60           ASSERT_EQ(info->dlpi_phnum, ehdr->e_phnum);
     61           break;
     62         }
     63       }
     64     }
     65     size_t count;
     66   } f = {};
     67   ASSERT_EQ(0, dl_iterate_phdr(Functor::Callback, &f));
     68 }
     69 
     70 #if __arm__
     71 static uintptr_t read_exidx_func(uintptr_t* entry) {
     72   int32_t offset = *entry;
     73   // Sign-extend from int31 to int32.
     74   if ((offset & 0x40000000) != 0) {
     75     offset += -0x7fffffff - 1;
     76   }
     77   return reinterpret_cast<uintptr_t>(entry) + offset;
     78 }
     79 __attribute__((__unused__)) static void another_function_in_same_ELF_file() {}
     80 #endif
     81 
     82 TEST(link, dl_unwind_find_exidx) {
     83 #if __arm__
     84   int count = 0;
     85   struct eit_entry_t {
     86     uintptr_t one;
     87     uintptr_t two;
     88   };
     89   eit_entry_t* entries = reinterpret_cast<eit_entry_t*>(dl_unwind_find_exidx(
     90       reinterpret_cast<_Unwind_Ptr>(read_exidx_func), &count));
     91   ASSERT_TRUE(entries != nullptr);
     92   ASSERT_GT(count, 0);
     93 
     94   // Sanity checks
     95   uintptr_t func = reinterpret_cast<uintptr_t>(read_exidx_func);
     96   bool found = false;
     97   for (int i = 0; i < count; ++i) {
     98     // Entries must have bit 31 clear.
     99     ASSERT_TRUE((entries[i].one & (1<<31)) == 0);
    100 
    101     uintptr_t exidx_func = read_exidx_func(&entries[i].one);
    102 
    103     // If our function is compiled for thumb, exception table contains our address - 1.
    104     if (func == exidx_func || func == exidx_func + 1) found = true;
    105 
    106     // Entries must be sorted. Some addresses may appear twice if function
    107     // is compiled for arm.
    108     if (i > 0) {
    109       EXPECT_GE(exidx_func, read_exidx_func(&entries[i - 1].one)) << i;
    110     }
    111   }
    112   ASSERT_TRUE(found);
    113 #else
    114   GTEST_LOG_(INFO) << "dl_unwind_find_exidx is an ARM-only API\n";
    115 #endif
    116 }
    117