• Home
  • Line#
  • Scopes#
  • Navigate#
  • Raw
  • Download
1 #include <unistd.h>
2 #include "tests/sys_mman.h"
3 #include <assert.h>
4 #include <stdlib.h>
5 
6 #include "valgrind.h"
7 
8 #define SUPERBLOCK_SIZE    100000
9 
10 //-------------------------------------------------------------------------
11 // Allocator
12 //-------------------------------------------------------------------------
13 
get_superblock(void)14 void* get_superblock(void)
15 {
16    void* p = mmap( 0, SUPERBLOCK_SIZE, PROT_READ|PROT_WRITE|PROT_EXEC,
17                    MAP_PRIVATE|MAP_ANONYMOUS, -1, 0 );
18 
19    assert(p != ((void*)(-1)));
20 
21    return p;
22 }
23 
24 // has a redzone
custom_alloc(int size)25 static void* custom_alloc(int size)
26 {
27 #define RZ  8
28    static void* hp     = 0;    // current heap pointer
29    static void* hp_lim = 0;    // maximum usable byte in current block
30    int          size2  = size + RZ*2;
31    void*        p;
32 
33    if (hp + size2 > hp_lim) {
34       hp = get_superblock();
35       hp_lim = hp + SUPERBLOCK_SIZE - 1;
36    }
37 
38    p = hp + RZ;
39    hp += size2;
40 
41    VALGRIND_MALLOCLIKE_BLOCK( p, size, RZ, /*is_zeroed*/1 );
42    return (void*)p;
43 }
44 
custom_free(void * p)45 static void custom_free(void* p)
46 {
47    // don't actually free any memory... but mark it as freed
48    VALGRIND_FREELIKE_BLOCK( p, RZ );
49 }
50 #undef RZ
51 
52 
53 
54 //-------------------------------------------------------------------------
55 // Rest
56 //-------------------------------------------------------------------------
57 
main(void)58 int main(void)
59 {
60    int* a = custom_alloc(400);   // All sizes are divisible by 16 -- no slop.
61    custom_free(a);
62 
63    a = custom_alloc(800);
64    custom_free(a);
65 
66    a = malloc(400);
67    free(a);
68 
69    a = malloc(800);
70    free(a);
71 
72    return 0;
73 }
74