/* This test case was originally written by Nicholas Nethercote. */ // This test covers all the different sources of values, both defined and // undefined. It only involves undefined condition errors. // // Nb: a stack frame is allocated when a signal is delivered. But it // immediately get written with stuff, so there's no significant possibility // of undefined values originating there. So we ignore it. (On platforms // like AMD64 that have a redzone just beyond the stack pointer there is a // possibility, but it's so slim we ignore it.) #include <stdio.h> #include <assert.h> #include <stdlib.h> #include "tests/sys_mman.h" #include <unistd.h> #include "../memcheck.h" int x = 0; int main(void) { assert(1 == sizeof(char)); assert(2 == sizeof(short)); assert(4 == sizeof(int)); assert(8 == sizeof(long long)); //------------------------------------------------------------------------ // Sources of undefined values //------------------------------------------------------------------------ // Stack, 32-bit { volatile int undef_stack_int; fprintf(stderr, "\nUndef 1 of 8 (stack, 32 bit)\n"); x += (undef_stack_int == 0x12345678 ? 10 : 21); } // Stack, 32-bit, recently modified. Nb: we have to do the register // mucking about to make sure that the modification isn't fenced by a // store/load pair and thus not seen (see origin-not-quite.c). { volatile int undef_stack_int; register int modified_undef_stack_int; fprintf(stderr, "\nUndef 2 of 8 (stack, 32 bit)\n"); modified_undef_stack_int = undef_stack_int; modified_undef_stack_int++; x += (modified_undef_stack_int == 0x1234 ? 11 : 22); } // Stack, 64-bit. XXX: gets reported with two identical origins. { volatile long long undef_stack_longlong; fprintf(stderr, "\nUndef 3 of 8 (stack, 64 bit)\n"); x += (undef_stack_longlong == 0x1234567812345678LL ? 11 : 22); } // Malloc block, uninitialised, 32-bit { int* ptr_to_undef_malloc_int = malloc(sizeof(int)); int undef_malloc_int = *ptr_to_undef_malloc_int; fprintf(stderr, "\nUndef 4 of 8 (mallocd, 32-bit)\n"); x += (undef_malloc_int == 0x12345678 ? 12 : 23); } // Realloc block, uninitialised { int* ptr_to_undef_malloc_int2 = malloc(sizeof(int)); // Allocate a big chunk to ensure that a new block is allocated. int* ptr_to_undef_realloc_int = realloc(ptr_to_undef_malloc_int2, 4096); // Have to move past the first 4 bytes, which were copied from the // malloc'd block. int undef_realloc_int = *(ptr_to_undef_realloc_int+1); fprintf(stderr, "\nUndef 5 of 8 (realloc)\n"); x += (undef_realloc_int == 0x12345678 ? 13 : 24); } // Custom-allocated block, non-zeroed { int undef_custom_alloc_int; VALGRIND_MALLOCLIKE_BLOCK(&undef_custom_alloc_int, sizeof(int), /*rzB*/0, /*is_zeroed*/0); fprintf(stderr, "\nUndef 6 of 8 (MALLOCLIKE_BLOCK)\n"); x += (undef_custom_alloc_int == 0x12345678 ? 14 : 25); } // Heap segment (brk), uninitialised // CURRENTLY DISABLED. Why? // - On Darwin, sbrk() is implemented via vm_allocate() which always zeroes // its allocated memory. For a while we used use a separate .exp file // for Darwin, but we add an extra printf on Darwin only so that it // cannot be successfully matched on non-Darwin platforms. // - On Ubuntu 9.04 configured with --enable-only32bit, the brk symbol // shows up as "???" // - Our current treatment of brk is suspect; whole new pages allocated // with brk should arguably be marked defined -- see the big comment // above track_new_mem_brk() in memcheck/mc_main.c. //#if defined(VGO_darwin) fprintf(stderr, "\nUndef 7 of 8 (brk)\n"); // fprintf(stderr, "\n(no complaint; sbrk initialises memory on Darwin)\n"); fprintf(stderr, "\n(currently disabled)\n"); //#else // { // int* ptr_to_new_brk_limit = sbrk(4096); // int undef_brk_int = *ptr_to_new_brk_limit; // fprintf(stderr, "\nUndef 7 of 8 (brk)\n"); // x += (undef_brk_int == 0x12345678 ? 15 : 26); // } //#endif // User block, marked as undefined { int undef_user_int = 0; (void) VALGRIND_MAKE_MEM_UNDEFINED(&undef_user_int, sizeof(int)); fprintf(stderr, "\nUndef 8 of 8 (MAKE_MEM_UNDEFINED)\n"); x += (undef_user_int == 0x12345678 ? 16 : 27); } //------------------------------------------------------------------------ // Sources of defined values //------------------------------------------------------------------------ // Heap block (calloc), initialised { int* ptr_to_def_calloc_int = calloc(1, sizeof(int)); int def_calloc_int = *ptr_to_def_calloc_int; fprintf(stderr, "\nDef 1 of 3\n"); x += (def_calloc_int == 0x12345678 ? 17 : 28); } // Custom-allocated block, non-zeroed { int def_custom_alloc_int = 0; fprintf(stderr, "\nDef 2 of 3\n"); VALGRIND_MALLOCLIKE_BLOCK(&def_custom_alloc_int, sizeof(int), /*rzB*/0, /*is_zeroed*/1); x += (def_custom_alloc_int == 0x12345678 ? 18 : 29); } // mmap block, initialised { int* ptr_to_def_mmap_int = mmap(0, 4096, PROT_READ, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0); int def_mmap_int = *ptr_to_def_mmap_int; fprintf(stderr, "\nDef 3 of 3\n"); x += (def_mmap_int == 0x12345678 ? 19 : 30); } return x; }