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1 /*
2  * Copyright (C) 2013 The Android Open Source Project
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *      http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 
17 #include <stdlib.h>
18 #include <string.h>
19 #include <sys/mman.h>
20 
21 #include <gtest/gtest.h>
22 
23 #include "../linker_block_allocator.h"
24 
25 #include <unistd.h>
26 
27 namespace {
28 
29 struct test_struct_nominal {
30   void* pointer;
31   ssize_t value;
32 };
33 
34 /*
35  * this one has size below allocator cap which is 2*sizeof(void*)
36  */
37 struct test_struct_small {
38   char dummy_str[5];
39 };
40 
41 /*
42  * 1009 byte struct (1009 is prime)
43  */
44 struct test_struct_larger {
45   char dummy_str[1009];
46 };
47 
48 static size_t kPageSize = sysconf(_SC_PAGE_SIZE);
49 };
50 
TEST(linker_allocator,test_nominal)51 TEST(linker_allocator, test_nominal) {
52   LinkerTypeAllocator<test_struct_nominal> allocator;
53 
54   test_struct_nominal* ptr1 = allocator.alloc();
55   ASSERT_TRUE(ptr1 != nullptr);
56   test_struct_nominal* ptr2 = allocator.alloc();
57   ASSERT_TRUE(ptr2 != nullptr);
58   // they should be next to each other.
59   ASSERT_EQ(ptr1+1, ptr2);
60 
61   ptr1->value = 42;
62 
63   allocator.free(ptr1);
64   allocator.free(ptr2);
65 }
66 
TEST(linker_allocator,test_small)67 TEST(linker_allocator, test_small) {
68   LinkerTypeAllocator<test_struct_small> allocator;
69 
70   char* ptr1 = reinterpret_cast<char*>(allocator.alloc());
71   char* ptr2 = reinterpret_cast<char*>(allocator.alloc());
72 
73   ASSERT_TRUE(ptr1 != nullptr);
74   ASSERT_TRUE(ptr2 != nullptr);
75   ASSERT_EQ(ptr1+2*sizeof(void*), ptr2);
76 }
77 
TEST(linker_allocator,test_larger)78 TEST(linker_allocator, test_larger) {
79   LinkerTypeAllocator<test_struct_larger> allocator;
80 
81   test_struct_larger* ptr1 = allocator.alloc();
82   test_struct_larger* ptr2 = allocator.alloc();
83 
84   ASSERT_TRUE(ptr1 != nullptr);
85   ASSERT_TRUE(ptr2 != nullptr);
86 
87   ASSERT_EQ(ptr1+1, ptr2);
88 
89   // lets allocate until we reach next page.
90   size_t n = kPageSize/sizeof(test_struct_larger) + 1 - 2;
91 
92   for (size_t i=0; i<n; ++i) {
93     ASSERT_TRUE(allocator.alloc() != nullptr);
94   }
95 
96   test_struct_larger* ptr_to_free = allocator.alloc();
97   ASSERT_TRUE(ptr_to_free != nullptr);
98   allocator.free(ptr1);
99 }
100 
protect_all()101 static void protect_all() {
102   LinkerTypeAllocator<test_struct_larger> allocator;
103 
104   // number of allocs to reach the end of first page
105   size_t n = kPageSize/sizeof(test_struct_larger) - 1;
106   test_struct_larger* page1_ptr = allocator.alloc();
107 
108   for (size_t i=0; i<n; ++i) {
109     allocator.alloc();
110   }
111 
112   test_struct_larger* page2_ptr = allocator.alloc();
113   allocator.protect_all(PROT_READ);
114   allocator.protect_all(PROT_READ | PROT_WRITE);
115   // check access
116   page2_ptr->dummy_str[23] = 27;
117   page1_ptr->dummy_str[13] = 11;
118 
119   allocator.protect_all(PROT_READ);
120   fprintf(stderr, "trying to access protected page");
121 
122   // this should result in segmentation fault
123   page1_ptr->dummy_str[11] = 7;
124 }
125 
TEST(linker_allocator,test_protect)126 TEST(linker_allocator, test_protect) {
127   testing::FLAGS_gtest_death_test_style = "threadsafe";
128   ASSERT_EXIT(protect_all(), testing::KilledBySignal(SIGSEGV), "trying to access protected page");
129 }
130 
131