1 
2 /* This test case was originally written by Nicholas Nethercote. */
3 
4 // This test covers all the different sources of values, both defined and
5 // undefined.  It only involves undefined condition errors.
6 //
7 // Nb: a stack frame is allocated when a signal is delivered.  But it
8 // immediately get written with stuff, so there's no significant possibility
9 // of undefined values originating there.  So we ignore it.  (On platforms
10 // like AMD64 that have a redzone just beyond the stack pointer there is a
11 // possibility, but it's so slim we ignore it.)
12 
13 #include <stdio.h>
14 #include <assert.h>
15 #include <stdlib.h>
16 #include "tests/sys_mman.h"
17 #include <unistd.h>
18 #include "../memcheck.h"
19 
20 int x = 0;
21 
22 int main(void)
23 {
24    assert(1 == sizeof(char));
25    assert(2 == sizeof(short));
26    assert(4 == sizeof(int));
27    assert(8 == sizeof(long long));
28 
29    //------------------------------------------------------------------------
30    // Sources of undefined values
31    //------------------------------------------------------------------------
32 
33    // Stack, 32-bit
34    {
35       volatile int undef_stack_int;
36       fprintf(stderr, "\nUndef 1 of 8 (stack, 32 bit)\n");
37       x += (undef_stack_int == 0x12345678 ? 10 : 21);
38    }
39 
40    // Stack, 32-bit, recently modified.  Nb: we have to do the register
41    // mucking about to make sure that the modification isn't fenced by a
42    // store/load pair and thus not seen (see origin-not-quite.c).
43    {
44       volatile int undef_stack_int;
45       register int modified_undef_stack_int;
46       fprintf(stderr, "\nUndef 2 of 8 (stack, 32 bit)\n");
47       modified_undef_stack_int = undef_stack_int;
48       modified_undef_stack_int++;
49       x += (modified_undef_stack_int == 0x1234 ? 11 : 22);
50    }
51 
52    // Stack, 64-bit.  XXX: gets reported with two identical origins.
53    {
54       volatile long long undef_stack_longlong;
55       fprintf(stderr, "\nUndef 3 of 8 (stack, 64 bit)\n");
56       x += (undef_stack_longlong == 0x1234567812345678LL ? 11 : 22);
57    }
58 
59    // Malloc block, uninitialised, 32-bit
60    {
61       int* ptr_to_undef_malloc_int = malloc(sizeof(int));
62       int  undef_malloc_int = *ptr_to_undef_malloc_int;
63       fprintf(stderr, "\nUndef 4 of 8 (mallocd, 32-bit)\n");
64       x += (undef_malloc_int == 0x12345678 ? 12 : 23);
65    }
66 
67    // Realloc block, uninitialised
68    {
69       int* ptr_to_undef_malloc_int2 = malloc(sizeof(int));
70          // Allocate a big chunk to ensure that a new block is allocated.
71       int* ptr_to_undef_realloc_int = realloc(ptr_to_undef_malloc_int2, 4096);
72          // Have to move past the first 4 bytes, which were copied from the
73          // malloc'd block.
74       int  undef_realloc_int = *(ptr_to_undef_realloc_int+1);
75       fprintf(stderr, "\nUndef 5 of 8 (realloc)\n");
76       x += (undef_realloc_int == 0x12345678 ? 13 : 24);
77    }
78 
79    // Custom-allocated block, non-zeroed
80    {
81       int  undef_custom_alloc_int;
82       VALGRIND_MALLOCLIKE_BLOCK(&undef_custom_alloc_int, sizeof(int),
83                                 /*rzB*/0, /*is_zeroed*/0);
84       fprintf(stderr, "\nUndef 6 of 8 (MALLOCLIKE_BLOCK)\n");
85       x += (undef_custom_alloc_int == 0x12345678 ? 14 : 25);
86    }
87 
88    // Heap segment (brk), uninitialised
89    // CURRENTLY DISABLED.  Why?
90    // - On Darwin, sbrk() is implemented via vm_allocate() which always zeroes
91    //   its allocated memory.  For a while we used use a separate .exp file
92    //   for Darwin, but we add an extra printf on Darwin only so that it
93    //   cannot be successfully matched on non-Darwin platforms.
94    // - On Ubuntu 9.04 configured with --enable-only32bit, the brk symbol
95    //   shows up as "???"
96    // - Our current treatment of brk is suspect;  whole new pages allocated
97    //   with brk should arguably be marked defined -- see the big comment
98    //   above track_new_mem_brk() in memcheck/mc_main.c.
99 //#if defined(VGO_darwin)
100       fprintf(stderr, "\nUndef 7 of 8 (brk)\n");
101 //      fprintf(stderr, "\n(no complaint; sbrk initialises memory on Darwin)\n");
102       fprintf(stderr, "\n(currently disabled)\n");
103 //#else
104 //   {
105 //      int* ptr_to_new_brk_limit = sbrk(4096);
106 //      int  undef_brk_int = *ptr_to_new_brk_limit;
107 //      fprintf(stderr, "\nUndef 7 of 8 (brk)\n");
108 //      x += (undef_brk_int == 0x12345678 ? 15 : 26);
109 //   }
110 //#endif
111 
112    // User block, marked as undefined
113    {
114       int  undef_user_int = 0;
115       (void) VALGRIND_MAKE_MEM_UNDEFINED(&undef_user_int, sizeof(int));
116       fprintf(stderr, "\nUndef 8 of 8 (MAKE_MEM_UNDEFINED)\n");
117       x += (undef_user_int == 0x12345678 ? 16 : 27);
118    }
119 
120    //------------------------------------------------------------------------
121    // Sources of defined values
122    //------------------------------------------------------------------------
123 
124    // Heap block (calloc), initialised
125    {
126       int* ptr_to_def_calloc_int = calloc(1, sizeof(int));
127       int  def_calloc_int = *ptr_to_def_calloc_int;
128       fprintf(stderr, "\nDef 1 of 3\n");
129       x += (def_calloc_int == 0x12345678 ? 17 : 28);
130    }
131 
132    // Custom-allocated block, non-zeroed
133    {
134       int  def_custom_alloc_int = 0;
135       fprintf(stderr, "\nDef 2 of 3\n");
136       VALGRIND_MALLOCLIKE_BLOCK(&def_custom_alloc_int, sizeof(int),
137                                 /*rzB*/0, /*is_zeroed*/1);
138       x += (def_custom_alloc_int == 0x12345678 ? 18 : 29);
139    }
140 
141    // mmap block, initialised
142    {
143       int* ptr_to_def_mmap_int =
144                mmap(0, 4096, PROT_READ, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
145       int def_mmap_int = *ptr_to_def_mmap_int;
146       fprintf(stderr, "\nDef 3 of 3\n");
147       x += (def_mmap_int == 0x12345678 ? 19 : 30);
148    }
149 
150    return x;
151 }
152