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      1 /*
      2  * Copyright (C) 2013 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 <stdlib.h>
     30 #include <string.h>
     31 #include <sys/mman.h>
     32 
     33 #include <gtest/gtest.h>
     34 
     35 #include "linker_block_allocator.h"
     36 
     37 #include <unistd.h>
     38 
     39 namespace {
     40 
     41 struct test_struct_nominal {
     42   void* pointer;
     43   ssize_t value;
     44 };
     45 
     46 /*
     47  * this one has size below allocator cap which is 2*sizeof(void*)
     48  */
     49 struct test_struct_small {
     50   char dummy_str[5];
     51 };
     52 
     53 /*
     54  * 1009 byte struct (1009 is prime)
     55  */
     56 struct test_struct_larger {
     57   char dummy_str[1009];
     58 };
     59 
     60 static size_t kPageSize = sysconf(_SC_PAGE_SIZE);
     61 };
     62 
     63 TEST(linker_allocator, test_nominal) {
     64   LinkerTypeAllocator<test_struct_nominal> allocator;
     65 
     66   test_struct_nominal* ptr1 = allocator.alloc();
     67   ASSERT_TRUE(ptr1 != nullptr);
     68   ASSERT_EQ(0U, reinterpret_cast<uintptr_t>(ptr1) % 16);
     69   test_struct_nominal* ptr2 = allocator.alloc();
     70   ASSERT_EQ(0U, reinterpret_cast<uintptr_t>(ptr2) % 16);
     71   ASSERT_TRUE(ptr2 != nullptr);
     72   // they should be next to each other.
     73   ASSERT_EQ(reinterpret_cast<uint8_t*>(ptr1)+16, reinterpret_cast<uint8_t*>(ptr2));
     74 
     75   ptr1->value = 42;
     76 
     77   allocator.free(ptr1);
     78   allocator.free(ptr2);
     79 }
     80 
     81 TEST(linker_allocator, test_small) {
     82   LinkerTypeAllocator<test_struct_small> allocator;
     83 
     84   char* ptr1 = reinterpret_cast<char*>(allocator.alloc());
     85   char* ptr2 = reinterpret_cast<char*>(allocator.alloc());
     86 
     87   ASSERT_TRUE(ptr1 != nullptr);
     88   ASSERT_EQ(0U, reinterpret_cast<uintptr_t>(ptr1) % 16);
     89   ASSERT_TRUE(ptr2 != nullptr);
     90   ASSERT_EQ(0U, reinterpret_cast<uintptr_t>(ptr2) % 16);
     91   ASSERT_EQ(ptr1+16, ptr2); // aligned to 16
     92 }
     93 
     94 TEST(linker_allocator, test_larger) {
     95   LinkerTypeAllocator<test_struct_larger> allocator;
     96 
     97   test_struct_larger* ptr1 = allocator.alloc();
     98   test_struct_larger* ptr2 = allocator.alloc();
     99 
    100   ASSERT_TRUE(ptr1 != nullptr);
    101   ASSERT_EQ(0U, reinterpret_cast<uintptr_t>(ptr1) % 16);
    102   ASSERT_TRUE(ptr2 != nullptr);
    103   ASSERT_EQ(0U, reinterpret_cast<uintptr_t>(ptr2) % 16);
    104 
    105   ASSERT_EQ(reinterpret_cast<uint8_t*>(ptr1) + 1024, reinterpret_cast<uint8_t*>(ptr2));
    106 
    107   // lets allocate until we reach next page.
    108   size_t n = kPageSize/sizeof(test_struct_larger) + 1 - 2;
    109 
    110   for (size_t i=0; i<n; ++i) {
    111     ASSERT_TRUE(allocator.alloc() != nullptr);
    112   }
    113 
    114   test_struct_larger* ptr_to_free = allocator.alloc();
    115   ASSERT_TRUE(ptr_to_free != nullptr);
    116   allocator.free(ptr1);
    117 }
    118 
    119 static void protect_all() {
    120   LinkerTypeAllocator<test_struct_larger> allocator;
    121 
    122   // number of allocs to reach the end of first page
    123   size_t n = kPageSize/sizeof(test_struct_larger) - 1;
    124   test_struct_larger* page1_ptr = allocator.alloc();
    125 
    126   for (size_t i=0; i<n; ++i) {
    127     allocator.alloc();
    128   }
    129 
    130   test_struct_larger* page2_ptr = allocator.alloc();
    131   allocator.protect_all(PROT_READ);
    132   allocator.protect_all(PROT_READ | PROT_WRITE);
    133   // check access
    134   page2_ptr->dummy_str[23] = 27;
    135   page1_ptr->dummy_str[13] = 11;
    136 
    137   allocator.protect_all(PROT_READ);
    138   fprintf(stderr, "trying to access protected page");
    139 
    140   // this should result in segmentation fault
    141   page1_ptr->dummy_str[11] = 7;
    142 }
    143 
    144 TEST(linker_allocator, test_protect) {
    145   testing::FLAGS_gtest_death_test_style = "threadsafe";
    146   ASSERT_EXIT(protect_all(), testing::KilledBySignal(SIGSEGV), "trying to access protected page");
    147 }
    148