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* mmap.cc (mmap64): Handle MAP_AUTOGROW flag.

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(fhandler_disk_file::mmap): Ditto. Clean conditional for readability.
	* include/sys/mman.h: Add MAP_AUTOGROW flag.
	* include/cygwin/version.h: Bump API minor version.
This commit is contained in:
Corinna Vinschen
2005-03-08 09:18:47 +00:00
parent 18edcecfbf
commit d2428633a6
4 changed files with 71 additions and 11 deletions
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7
winsup/cygwin/ChangeLog
View File

@ -1,3 +1,10 @@
2005-03-07 Corinna Vinschen <corinna@vinschen.de>
* mmap.cc (mmap64): Handle MAP_AUTOGROW flag.
(fhandler_disk_file::mmap): Ditto. Clean conditional for readability.
* include/sys/mman.h: Add MAP_AUTOGROW flag.
* include/cygwin/version.h: Bump API minor version.
2005-03-08 Christopher Faylor <cgf@timesys.com>
* dcrt0.cc (dll_crt0_0): Eliminate muto::init call.

3
winsup/cygwin/include/cygwin/version.h
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@ -250,12 +250,13 @@ details. */
120: Export basename, dirname.
122: Export statvfs, fstatvfs.
123: Export utmpxname.
124: Add MAP_AUTOGROW flag to mmap.
*/
/* Note that we forgot to bump the api for ualarm, strtoll, strtoull */
#define CYGWIN_VERSION_API_MAJOR 0
#define CYGWIN_VERSION_API_MINOR 123
#define CYGWIN_VERSION_API_MINOR 124
/* There is also a compatibity version number associated with the
shared memory regions. It is incremented when incompatible

3
winsup/cygwin/include/sys/mman.h
View File

@ -30,6 +30,9 @@ extern "C" {
#define MAP_FIXED 0x10
#define MAP_ANONYMOUS 0x20
#define MAP_ANON MAP_ANONYMOUS
/* Non-standard flag */
#define MAP_AUTOGROW 0x8000 /* Grow underlying object to mapping size.
File must be opened for writing. */
#define MAP_FAILED ((void *)-1)

67
winsup/cygwin/mmap.cc
View File

@ -587,10 +587,12 @@ mmap64 (void *addr, size_t len, int prot, int flags, int fd, _off64_t off)
DWORD high;
DWORD low = GetFileSize (fh->get_handle (), &high);
_off64_t fsiz = ((_off64_t)high << 32) + low;
/* Don't allow mappings beginning beyond EOF since Windows can't
handle that POSIX like. FIXME: Still looking for a good idea
to allow that nevertheless. */
if (gran_off >= fsiz)
handle that POSIX like, unless MAP_AUTOGROW flag is set, which
mimics Windows behaviour. FIXME: Still looking for a good idea
to allow that under POSIX rules. */
if (gran_off >= fsiz && !(flags & MAP_AUTOGROW))
{
set_errno (ENXIO);
ReleaseResourceLock (LOCK_MMAP_LIST, READ_LOCK | WRITE_LOCK,
@ -598,11 +600,31 @@ mmap64 (void *addr, size_t len, int prot, int flags, int fd, _off64_t off)
return MAP_FAILED;
}
/* Don't map beyond EOF. Windows would change the file to the
new length otherwise, in contrast to POSIX. */
new length otherwise, in contrast to POSIX. Allow mapping
beyon EOF if MAP_AUTOGROW flag is set. */
fsiz -= gran_off;
if (gran_len > fsiz)
{
if ((flags & MAP_AUTOGROW) && (off - gran_off) + len > fsiz)
{
/* Check if file has been opened for writing. */
if (!(fh->get_access () & GENERIC_WRITE))
{
set_errno (EINVAL);
ReleaseResourceLock (LOCK_MMAP_LIST, READ_LOCK | WRITE_LOCK,
"mmap");
return MAP_FAILED;
}
gran_len = (off - gran_off) + len;
}
else
gran_len = fsiz;
}
/* If the requested len is <= file size, drop the MAP_AUTOGROW flag.
This simplifes fhandler::mmap's job. */
if ((flags & MAP_AUTOGROW) && gran_len <= fsiz)
flags &= ~MAP_AUTOGROW;
}
DWORD access = (prot & PROT_WRITE) ? FILE_MAP_WRITE : FILE_MAP_READ;
/* copy-on-write doesn't work at all on 9x using anonymous maps.
@ -1019,6 +1041,7 @@ fhandler_disk_file::mmap (caddr_t *addr, size_t len, DWORD access,
}
HANDLE h;
DWORD high, low;
/* On 9x/ME try first to open the mapping by name when opening a
shared file object. This is needed since 9x/ME only shares
@ -1037,12 +1060,37 @@ fhandler_disk_file::mmap (caddr_t *addr, size_t len, DWORD access,
debug_printf ("named sharing");
if (!(h = OpenFileMapping (access, TRUE, namebuf)))
h = CreateFileMapping (get_handle (), &sec_none, protect, 0, 0, namebuf);
h = CreateFileMapping (get_handle (), &sec_none, protect, 0, 0,
namebuf);
}
else if (get_handle () == INVALID_HANDLE_VALUE)
{
/* Standard anonymous mapping needs non-zero len. */
h = CreateFileMapping (get_handle (), &sec_none, protect, 0, len, NULL);
}
else if (flags & MAP_AUTOGROW)
{
high = (off + len) >> 32;
low = (off + len) & UINT32_MAX;
/* Auto-grow in CreateFileMapping only works if the protection is
PAGE_READWRITE. So, first we call CreateFileMapping with
PAGE_READWRITE, then, if the requested protection is different, we
close the mapping and reopen it again with the correct protection,
*iff* auto-grow worked. */
h = CreateFileMapping (get_handle (), &sec_none, PAGE_READWRITE,
high, low, NULL);
if (h && protect != PAGE_READWRITE)
{
CloseHandle (h);
h = CreateFileMapping (get_handle (), &sec_none, protect,
high, low, NULL);
}
}
else
h = CreateFileMapping (get_handle (), &sec_none, protect, 0,
get_handle () == INVALID_HANDLE_VALUE ? len : 0,
NULL);
{
/* Zero len creates mapping for whole file. */
h = CreateFileMapping (get_handle (), &sec_none, protect, 0, 0, NULL);
}
if (!h)
{
__seterrno ();
@ -1050,7 +1098,8 @@ fhandler_disk_file::mmap (caddr_t *addr, size_t len, DWORD access,
return INVALID_HANDLE_VALUE;
}
DWORD high = off >> 32, low = off & UINT32_MAX;
high = off >> 32;
low = off & UINT32_MAX;
void *base = NULL;
/* If a non-zero address is given, try mapping using the given address first.
If it fails and flags is not MAP_FIXED, try again with NULL address. */