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* mmap.cc (list::try_map): New method, implementing trying to map

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within another already existing map, moved from mmap64 here.
	(mmap64): Just call try_map now.
	(fhandler_dev_zero::fixup_mmap_after_fork): Always create new private
	map with PAGE_READWRITE protection.
	(fixup_mmaps_after_fork): Fix comment.
This commit is contained in:
Corinna Vinschen 2005-11-30 15:05:48 +00:00
parent e4809ddd20
commit b0c3293ecc
2 changed files with 68 additions and 44 deletions
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9
winsup/cygwin/ChangeLog
View File

@ -1,3 +1,12 @@
2005-11-30 Corinna Vinschen <corinna@vinschen.de>
* mmap.cc (list::try_map): New method, implementing trying to map
within another already existing map, moved from mmap64 here.
(mmap64): Just call try_map now.
(fhandler_dev_zero::fixup_mmap_after_fork): Always create new private
map with PAGE_READWRITE protection.
(fixup_mmaps_after_fork): Fix comment.
2005-11-29 Corinna Vinschen <corinna@vinschen.de>
* include/cygwin/version.h: Bump API minor version.

103
winsup/cygwin/mmap.cc
View File

@ -453,6 +453,7 @@ class list
mmap_record *search_record (_off64_t off, DWORD len);
long search_record (caddr_t addr, DWORD len, caddr_t &m_addr, DWORD &m_len,
long start);
caddr_t try_map (void *addr, size_t len, int flags, _off64_t off);
};
class map
@ -726,6 +727,52 @@ list::del_record (int i)
return !nrecs;
}
caddr_t
list::try_map (void *addr, size_t len, int flags, _off64_t off)
{
mmap_record *rec;
if (off == 0 && !fixed (flags))
{
/* If MAP_FIXED isn't given, check if this mapping matches into the
chunk of another already performed mapping. */
if ((rec = search_record (off, len)) != NULL
&& rec->compatible_flags (flags))
{
if ((off = rec->map_pages (off, len)) == (_off64_t)-1)
return (caddr_t) MAP_FAILED;
return (caddr_t) rec->get_address () + off;
}
}
else if (fixed (flags))
{
/* If MAP_FIXED is given, test if the requested area is in an
unmapped part of an still active mapping. This can happen
if a memory region is unmapped and remapped with MAP_FIXED. */
caddr_t u_addr;
DWORD u_len;
long record_idx = -1;
if ((record_idx = search_record ((caddr_t) addr, len, u_addr, u_len,
record_idx)) >= 0)
{
rec = get_record (record_idx);
if (u_addr > (caddr_t) addr || u_addr + len < (caddr_t) addr + len
|| !rec->compatible_flags (flags))
{
/* Partial match only, or access mode doesn't match. */
/* FIXME: Handle partial mappings gracefully if adjacent
memory is available. */
set_errno (EINVAL);
return (caddr_t) MAP_FAILED;
}
if (!rec->map_pages ((caddr_t) addr, len))
return (caddr_t) MAP_FAILED;
return (caddr_t) addr;
}
}
return NULL;
}
list *
map::get_list_by_fd (int fd)
{
@ -890,46 +937,13 @@ mmap64 (void *addr, size_t len, int prot, int flags, int fd, _off64_t off)
/* Test if an existing anonymous mapping can be recycled. */
if (map_list && anonymous (flags))
{
if (off == 0 && !fixed (flags))
{
/* If MAP_FIXED isn't given, check if this mapping matches into the
chunk of another already performed mapping. */
if ((rec = map_list->search_record (off, len)) != NULL
&& rec->compatible_flags (flags))
{
if ((off = rec->map_pages (off, len)) == (_off64_t)-1)
goto out;
ret = rec->get_address () + off;
goto out;
}
}
else if (fixed (flags))
{
/* If MAP_FIXED is given, test if the requested area is in an
unmapped part of an still active mapping. This can happen
if a memory region is unmapped and remapped with MAP_FIXED. */
caddr_t u_addr;
DWORD u_len;
long record_idx = -1;
if ((record_idx = map_list->search_record ((caddr_t)addr, len,
u_addr, u_len,
record_idx)) >= 0)
{
rec = map_list->get_record (record_idx);
if (u_addr > (caddr_t)addr || u_addr + len < (caddr_t)addr + len
|| !rec->compatible_flags (flags))
{
/* Partial match only, or access mode doesn't match. */
/* FIXME: Handle partial mappings gracefully if adjacent
memory is available. */
set_errno (EINVAL);
goto out;
}
if (!rec->map_pages ((caddr_t)addr, len))
goto out;
ret = (caddr_t)addr;
goto out;
}
caddr_t tried = map_list->try_map (addr, len, flags, off);
/* try_map returns NULL if no map matched, otherwise it returns
a valid address, of MAP_FAILED in case of a fatal error. */
if (tried)
{
ret = tried;
goto out;
}
}
@ -1434,9 +1448,11 @@ fhandler_dev_zero::fixup_mmap_after_fork (HANDLE h, int prot, int flags,
void *base;
if (priv (flags))
{
DWORD protect = gen_protect (prot, flags);
DWORD alloc_type = MEM_RESERVE | (noreserve (flags) ? 0 : MEM_COMMIT);
base = VirtualAlloc (address, size, alloc_type, protect);
/* Always allocate R/W so that ReadProcessMemory doesn't fail
due to a non-writable target address. The protection is
set to the correct one anyway in the fixup loop. */
base = VirtualAlloc (address, size, alloc_type, PAGE_READWRITE);
}
else
base = mmap_func->MapView (h, address, size, prot, flags, offset);
@ -1719,8 +1735,7 @@ fixup_mmaps_after_fork (HANDLE parent)
return -1;
}
}
/* Set child page protection to parent protection if
protection differs from original protection. */
/* Set child page protection to parent protection */
if (!VirtualProtect (address, mbi.RegionSize,
mbi.Protect, &old_prot))
{