custom_alloc.c revision ed07e00d438c74b7a23c01bfffde77e3968305e4
1202a77d28ac251545f6f998a974690212309b927Iliyan Malchev#include <unistd.h> 24d35af868a667e7792cf54a62ded8df85ece8d03Naseer Ahmed#include "tests/sys_mman.h" 3202a77d28ac251545f6f998a974690212309b927Iliyan Malchev#include <assert.h> 4ca3f7173ece307bcb647e0058d9fab5573558364Mathew Karimpanal#include <stdlib.h> 54d35af868a667e7792cf54a62ded8df85ece8d03Naseer Ahmed 64d35af868a667e7792cf54a62ded8df85ece8d03Naseer Ahmed#include "valgrind.h" 74d35af868a667e7792cf54a62ded8df85ece8d03Naseer Ahmed 84d35af868a667e7792cf54a62ded8df85ece8d03Naseer Ahmed#define SUPERBLOCK_SIZE 100000 94d35af868a667e7792cf54a62ded8df85ece8d03Naseer Ahmed 1056f610dd235b577725198e9341caae92379fdf23Saurabh Shah//------------------------------------------------------------------------- 11d5e3e404e1344eb2148c8df9f3e35d841ddd4285Saurabh Shah// Allocator 12ca3f7173ece307bcb647e0058d9fab5573558364Mathew Karimpanal//------------------------------------------------------------------------- 134d35af868a667e7792cf54a62ded8df85ece8d03Naseer Ahmed 144c588a200c537224d4eb5f63fb0a88f791511ff2Naseer Ahmedvoid* get_superblock(void) 154c588a200c537224d4eb5f63fb0a88f791511ff2Naseer Ahmed{ 164c588a200c537224d4eb5f63fb0a88f791511ff2Naseer Ahmed void* p = mmap( 0, SUPERBLOCK_SIZE, PROT_READ|PROT_WRITE|PROT_EXEC, 174c588a200c537224d4eb5f63fb0a88f791511ff2Naseer Ahmed MAP_PRIVATE|MAP_ANONYMOUS, -1, 0 ); 18ff4f0254be575a264504687c407e0db2fd5573d7Naseer Ahmed 19d551ebe2cb65d9da47d3e25f6004b8870afec8b4Naseer Ahmed assert(p != ((void*)(-1))); 206c43ebed229c5d1e00c6d41638cd2f8e3cb979b7Arun Kumar K.R 21d5e3e404e1344eb2148c8df9f3e35d841ddd4285Saurabh Shah return p; 22d5e3e404e1344eb2148c8df9f3e35d841ddd4285Saurabh Shah} 234c588a200c537224d4eb5f63fb0a88f791511ff2Naseer Ahmed 24202a77d28ac251545f6f998a974690212309b927Iliyan Malchev// has a redzone 25static 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 45static 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 58int 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