+2011-05-28 Ryan Johnson <ryan.johnson@cs.utoronto.ca>
+
+ * dll_init.cc (dll_list::alloc): Initialize dll::image_size.
+ (reserve_at): Don't reserve space needed by the target dll if the
+ latter overlaps the free region to be blocked.
+ (dll_list::load_after_fork): Use new version of reserve_at.
+ * dll_init.h (dll::image_size): New member.
+ (pefile): New struct.
+
2011-05-28 Christopher Faylor <me.cygwin2011@cgf.cx>
Ryan Johnson <ryan.johnson@cs.utoronto.ca>
d->handle = h;
d->has_dtors = true;
d->p = p;
+ d->image_size = ((pefile*)h)->optional_hdr ()->SizeOfImage;
d->type = type;
if (end == NULL)
end = &start; /* Point to "end" of dll chain. */
}
}
-/* Mark one page at "here" as reserved. This may force
- Windows NT to load a DLL elsewhere. */
+/* Reserve the chunk of free address space starting _here_ and (usually)
+ covering at least _dll_size_ bytes. However, we must take care not
+ to clobber the dll's target address range because it often overlaps.
+ */
static DWORD
-reserve_at (const PWCHAR name, DWORD here)
+reserve_at (const PWCHAR name, DWORD here, DWORD dll_base, DWORD dll_size)
{
DWORD size;
MEMORY_BASIC_INFORMATION mb;
if (!VirtualQuery ((void *) here, &mb, sizeof (mb)))
- size = 64 * 1024;
-
+ api_fatal ("couldn't examine memory at %08lx while mapping %W, %E",
+ here, name);
if (mb.State != MEM_FREE)
return 0;
size = mb.RegionSize;
+
+ // don't clobber the space where we want the dll to land
+ DWORD end = here + size;
+ DWORD dll_end = dll_base + dll_size;
+ if (dll_base < here && dll_end > here)
+ here = dll_end; // the dll straddles our left edge
+ else if (dll_base >= here && dll_base < end)
+ end = dll_base; // the dll overlaps partly or fully to our right
+
+ size = end - here;
if (!VirtualAlloc ((void *) here, size, MEM_RESERVE, PAGE_NOACCESS))
api_fatal ("couldn't allocate memory %p(%d) for '%W' alignment, %E\n",
here, size, name);
can in the child, due to differences in the load ordering.
Block memory at it's preferred address and try again. */
if ((DWORD) h > (DWORD) d->handle)
- preferred_block = reserve_at (d->name, (DWORD) h);
+ preferred_block = reserve_at (d->name, (DWORD) h,
+ (DWORD) d->handle, d->image_size);
}
}
int count;
bool has_dtors;
dll_type type;
+ DWORD image_size;
WCHAR name[1];
void detach ();
int init ();
dll_list () { protect.init ("dll_list"); }
};
+/* References:
+ http://msdn.microsoft.com/en-us/windows/hardware/gg463125
+ http://msdn.microsoft.com/en-us/library/ms809762.aspx
+*/
+struct pefile
+{
+ IMAGE_DOS_HEADER dos_hdr;
+
+ char* rva (long offset) { return (char*) this + offset; }
+ PIMAGE_NT_HEADERS32 pe_hdr () { return (PIMAGE_NT_HEADERS32) rva (dos_hdr.e_lfanew); }
+ PIMAGE_OPTIONAL_HEADER32 optional_hdr () { return &pe_hdr ()->OptionalHeader; }
+ PIMAGE_DATA_DIRECTORY idata_dir (DWORD which)
+ {
+ PIMAGE_OPTIONAL_HEADER32 oh = optional_hdr ();
+ return (which < oh->NumberOfRvaAndSizes)? oh->DataDirectory + which : 0;
+ }
+};
+
extern dll_list dlls;
void dll_global_dtors ();