r9749@danube: weasel | 2006-09-14 06:53:12 +0200

 Do not graciously increase the size to be mmaped if the current size already is
 at a page_size boundary.  This is important since if a file has a size of zero
 and we mmap() it with length > 0, then accessing the mmaped memory area causes
 a bus error.  However, if we pass a length of 0 to mmap() it will return with -1
 and things work from there.


svn:r8387

src/common/compat.c

@@ -130,7 +130,7 @@ tor_mmap_file(const char *filename)
   lseek(fd, 0, SEEK_SET);
   /* ensure page alignment */
   page_size = getpagesize();
-  size += (page_size + (page_size-(size%page_size)));
+  size += (size%page_size) ? page_size-(size%page_size) : 0;
 
   string = mmap(0, size, PROT_READ, MAP_PRIVATE, fd, 0);
   if (string == MAP_FAILED) {