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  1. #include <iostream>
  2. #include <stdio.h>
  3. #include <stddef.h>
  4. #include <unistd.h>
  5. #include <sys/mman.h>
  6. #include <vector>
  7.  
  8. void* malloc(size_t size) {
  9.   write(STDOUT_FILENO, "malloc... ", 10);
  10.   size += sizeof(size_t);
  11.   int page_size = getpagesize();
  12.   int rem = size % page_size;
  13.   if (rem > 0) {
  14.     size += page_size - rem;
  15.   }
  16.   void* addr = mmap(0, size, PROT_READ | PROT_WRITE,
  17.                     MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
  18.   if (addr == MAP_FAILED) {
  19.     write(STDOUT_FILENO, "fail\n", 5);
  20.     return NULL;
  21.   }
  22.   write(STDOUT_FILENO, "ok\n", 3);
  23.   *(size_t*)addr = size;
  24.   return (size_t*)addr + 1;
  25. }
  26.  
  27. void free (void *ptr) {
  28.   write(STDOUT_FILENO, "free... ", 8);
  29.   size_t* real_ptr = (size_t*)ptr - 1;
  30.   if (!munmap(real_ptr, *real_ptr)) {
  31.     write(STDOUT_FILENO, "ok\n", 3);
  32.   } else {
  33.     write(STDOUT_FILENO, "fail\n", 5);
  34.   }
  35. }
  36.  
  37.  
  38. int main() {
  39. 	std::vector<int> a;
  40. 	a.push_back(42);
  41. 	a.push_back(56);
  42.  
  43. 	return 0;
  44. }
Success #stdin #stdout 0s 4520KB
comments (?)
stdin 
Standard input is empty
stdout 
malloc... ok
malloc... ok
malloc... ok
free... ok
free... ok
https://ideone.com/bsm6Hb
language:
C++ 4.3.2 (gcc-4.3.2)
created:
5 years ago
visibility:
secret

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