diff options
| -rw-r--r-- | winsup/cygwin/mmap.cc | 35 |
1 files changed, 24 insertions, 11 deletions
diff --git a/winsup/cygwin/mmap.cc b/winsup/cygwin/mmap.cc index 8b1aedc48..797373742 100644 --- a/winsup/cygwin/mmap.cc +++ b/winsup/cygwin/mmap.cc @@ -834,7 +834,7 @@ public: { /* If it points to a free area, big enough to fulfill the request, return the address. */ - if (VirtualQuery (in_addr, &mbi, sizeof mbi) + if (VirtualQuery (in_addr, &mbi, sizeof mbi) && mbi.State == MEM_FREE && mbi.RegionSize >= size) return in_addr; @@ -1075,14 +1075,17 @@ mmap64 (void *addr, size_t len, int prot, int flags, int fd, off_t off) } fsiz -= off; /* We're creating the pages beyond EOF as reserved, anonymous pages. - Note that this isn't done in 64 bit environments since apparently - 64 bit systems don't support the AT_ROUND_TO_PAGE flag, which is - required to get this right. Too bad. */ + Note that 64 bit environments don't support the AT_ROUND_TO_PAGE + flag, which is required to get this right for the remainder of + the first 64K block the file ends in. We perform the workaround + nevertheless to support expectations that the range mapped beyond + EOF can be safely munmap'ed instead of being taken by another, + totally unrelated mapping. */ + if ((off_t) len > fsiz && !autogrow (flags)) + orig_len = len; #ifdef __i386__ - if (!wincap.is_wow64 () - && (((off_t) len > fsiz && !autogrow (flags)) - || roundup2 (len, wincap.page_size ()) - < roundup2 (len, pagesize))) + else if (!wincap.is_wow64 () && roundup2 (len, wincap.page_size ()) + < roundup2 (len, pagesize)) orig_len = len; #endif if ((off_t) len > fsiz) @@ -1185,12 +1188,22 @@ go_ahead: raise a SIGBUS when trying to access them. AT_ROUND_TO_PAGE and page protection on shared pages is only supported by the 32 bit environment, so don't even try on 64 bit or even WOW64. - This is accomplished by not setting orig_len on 64 bit above. */ - len = roundup2 (len, wincap.page_size ()); + This results in an allocation gap in the first 64K block the file + ends in, but there's nothing at all we can do about that. */ +#ifdef __x86_64__ + len = roundup2 (len, wincap.allocation_granularity ()); +#else + len = roundup2 (len, wincap.is_wow64 () ? wincap.allocation_granularity () + : wincap.page_size ()); +#endif if (orig_len - len) { orig_len -= len; - size_t valid_page_len = orig_len % pagesize; + size_t valid_page_len = 0; +#ifndef __x86_64__ + if (!wincap.is_wow64 ()) + valid_page_len = orig_len % pagesize; +#endif size_t sigbus_page_len = orig_len - valid_page_len; caddr_t at_base = base + len; |