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* 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.
This commit is contained in:
Christopher Faylor 2011-05-28 20:55:34 +00:00
parent 07f89f85db
commit 6cd2e18523
3 changed files with 48 additions and 6 deletions
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9
winsup/cygwin/ChangeLog
View File

@ -1,3 +1,12 @@
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>

26
winsup/cygwin/dll_init.cc
View File

@ -161,6 +161,7 @@ dll_list::alloc (HINSTANCE h, per_process *p, dll_type type)
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. */
@ -292,21 +293,33 @@ release_upto (const PWCHAR name, DWORD here)
}
}
/* 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);
@ -384,7 +397,8 @@ dll_list::load_after_fork (HANDLE parent)
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);
}
}

19
winsup/cygwin/dll_init.h
View File

@ -52,6 +52,7 @@ struct dll
int count;
bool has_dtors;
dll_type type;
DWORD image_size;
WCHAR name[1];
void detach ();
int init ();
@ -109,6 +110,24 @@ public:
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 ();