diff options
Diffstat (limited to 'src/alloc.c')
| -rw-r--r-- | src/alloc.c | 32 |
1 files changed, 28 insertions, 4 deletions
diff --git a/src/alloc.c b/src/alloc.c index bc48f7bb3b4..5ab28bc0cde 100644 --- a/src/alloc.c +++ b/src/alloc.c @@ -66,6 +66,14 @@ Boston, MA 02110-1301, USA. */ extern POINTER_TYPE *sbrk (); #endif +#ifdef HAVE_FCNTL_H +#define INCLUDED_FCNTL +#include <fcntl.h> +#endif +#ifndef O_WRONLY +#define O_WRONLY 1 +#endif + #ifdef DOUG_LEA_MALLOC #include <malloc.h> @@ -4498,21 +4506,37 @@ int valid_lisp_object_p (obj) Lisp_Object obj; { + void *p; #if !GC_MARK_STACK - /* Cannot determine this. */ - return -1; + int fd; #else - void *p; struct mem_node *m; +#endif if (INTEGERP (obj)) return 1; p = (void *) XPNTR (obj); - if (PURE_POINTER_P (p)) return 1; +#if !GC_MARK_STACK + /* We need to determine whether it is safe to access memory at + address P. Obviously, we cannot just access it (we would SEGV + trying), so we trick the o/s to tell us whether p is a valid + pointer. Unfortunately, we cannot use NULL_DEVICE here, as + emacs_write may not validate p in that case. */ + if ((fd = emacs_open("__Valid__Lisp__Object__", O_CREAT | O_WRONLY | O_TRUNC, 0666)) >= 0) + { + int valid = emacs_write(fd, (char *)p, 16) == 16; + emacs_close(fd); + unlink("__Valid__Lisp__Object__"); + return valid; + } + + return -1; +#else + m = mem_find (p); if (m == MEM_NIL) |