diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/mapalloc.c | 19 |
1 files changed, 11 insertions, 8 deletions
diff --git a/src/mapalloc.c b/src/mapalloc.c index 69e87fe..5becc59 100644 --- a/src/mapalloc.c +++ b/src/mapalloc.c @@ -2,6 +2,8 @@ #include <fcntl.h> #include <limits.h> #include <stdint.h> +#include <stdio.h> +#include <stdlib.h> #include <string.h> #include <sys/mman.h> #include <unistd.h> @@ -29,7 +31,7 @@ struct bucket { static struct bucket *get_bucket(void *ptr) { uintptr_t addr = (uintptr_t)ptr; - return NULL; + return addr ? NULL : NULL; } void *map_calloc(size_t nelem, size_t elsize) @@ -50,27 +52,27 @@ void *map_malloc(size_t n) int prot = PROT_READ | PROT_WRITE; int flags = MAP_PRIVATE; - /* round up to PAGESIZE, add 2 * PAGESIZE */ size_t alloc = n; if (n % PAGESIZE != 0) { - alloc += n % PAGESIZE; + alloc += PAGESIZE - (n % PAGESIZE); } alloc += 2 * PAGESIZE; #ifdef MAP_ANONYMOUS flags = MAP_ANONYMOUS; #else - fd = open("/dev/null", O_RDONLY); + fd = open("/dev/zero", O_RDONLY); #endif - void *ptr = mmap(NULL, alloc, prot, flags, fd, 0); + /* declare as char* so simple pointer arithmetic is possible */ + char *ptr = mmap(NULL, alloc, prot, flags, fd, 0); if (fd != -1) { close(fd); } mprotect(ptr, PAGESIZE, PROT_NONE); - mprotect((char*)ptr + alloc - PAGESIZE, PAGESIZE, PROT_NONE); + mprotect(ptr + alloc - PAGESIZE, PAGESIZE, PROT_NONE); /* struct bucket *b = get_bucket(ptr); @@ -78,7 +80,7 @@ void *map_malloc(size_t n) b->allocated = alloc; */ - return ptr; + return ptr + PAGESIZE; } void *map_realloc(void *ptr, size_t n) @@ -97,6 +99,7 @@ void map_free(void *ptr) struct bucket *b = get_bucket(ptr); if (b == NULL) { - /* attempting to free() an invalid pointer */ + fprintf(stderr, "attempt to free() invalid pointer %p\n", ptr); + abort(); } } |