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CVS patch #477161: New "access" keyword for mmap, from Jay T Miller. 

This gives mmap() on Windows the ability to create read-only, write-
through and copy-on-write mmaps.  A new keyword argument is introduced
because the mmap() signatures diverged between Windows and Unix, so
while they (now) both support this functionality, there wasn't a way to
spell it in a common way without introducing a new spelling gimmick.
The old spellings are still accepted, so there isn't a backward-
compatibility issue here.
This commit is contained in:
Tim Peters 2001-11-13 23:11:19 +00:00
parent afeb2a4d89
commit 5ebfd36afa
5 changed files with 411 additions and 144 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

162
Doc/lib/libmmap.tex
View File

@ -1,5 +1,5 @@
\section{\module{mmap} ---
Memory-mapped file support}
Memory-mapped file support}
\declaremodule{builtin}{mmap}
\modulesynopsis{Interface to memory-mapped files for Unix and Windows.}
@ -23,36 +23,67 @@ If you wish to map an existing Python file object, use its
\function{os.open()} function, which returns a file descriptor
directly (the file still needs to be closed when done).
\begin{funcdesc}{mmap}{fileno, length\optional{, tagname}}
\strong{(Windows version)} Maps \var{length} bytes from the file
specified by the file handle \var{fileno}, and returns a mmap object.
If \var{length} is \code{0}, the maximum length of the map will be the
current size of the file when \function{mmap()} is called.
\var{tagname}, if specified and not \code{None}, is a string giving a
tag name for the mapping. Windows allows you to have many different
mappings against the same file. If you specify the name of an
existing tag, that tag is opened, otherwise a new tag of this name is
created. If this parameter is omitted or \code{None}, the mapping is
created without a name. Avoiding the use of the tag parameter will
assist in keeping your code portable between \UNIX{} and Windows.
\begin{funcdesc}{mmap}{fileno, length\optional{, tagname\optional{, access}}}
\strong{(Windows version)} Maps \var{length} bytes from the file
specified by the file handle \var{fileno}, and returns a mmap
object. If \var{length} is \code{0}, the maximum length of the map
will be the current size of the file when \function{mmap()} is
called.
\var{tagname}, if specified and not \code{None}, is a string giving
a tag name for the mapping. Windows allows you to have many
different mappings against the same file. If you specify the name
of an existing tag, that tag is opened, otherwise a new tag of this
name is created. If this parameter is omitted or \code{None}, the
mapping is created without a name. Avoiding the use of the tag
parameter will assist in keeping your code portable between \UNIX{}
and Windows.
\var{access} may be specified as an optional keyword parameter.
\var{access} accepts one of three values: \constant{ACCESS_READ},
\constant{ACCESS_WRITE}, or \constant{ACCESS_COPY} to specify
readonly, write-through or copy-on-write memory respectively.
\var{access} can be used on both \UNIX{} and Windows. If
\var{access} is not specified, Windows mmap returns a write-through
mapping. The initial memory values for all three access types are
taken from the specified file. Assignment to an
\constant{ACCESS_READ} memory map raises a \exception{TypeError}
exception. Assignment to an \constant{ACCESS_WRITE} memory map
affects both memory and the underlying file. Assigment to an
\constant{ACCESS_COPY} memory map affects memory but does not update
the underlying file.
\end{funcdesc}
\begin{funcdesc}{mmap}{fileno, length\optional{, flags\optional{, prot}}}
\strong{(\UNIX{} version)} Maps \var{length} bytes from the file
specified by the file descriptor \var{fileno}, and returns a mmap object.
\var{flags} specifies the nature of the mapping.
\constant{MAP_PRIVATE} creates a private copy-on-write mapping, so
changes to the contents of the mmap object will be private to this
process, and \constant{MAP_SHARED} creates a mapping that's shared
with all other processes mapping the same areas of the file.
The default value is \constant{MAP_SHARED}.
\var{prot}, if specified, gives the desired memory protection; the two
most useful values are \constant{PROT_READ} and \constant{PROT_WRITE},
to specify that the pages may be read or written.
\var{prot} defaults to \constant{PROT_READ | PROT_WRITE}.
\begin{funcdesc}{mmap}{fileno, length\optional{, flags\optional{, prot\optional{, access}}}}
\strong{(\UNIX{} version)} Maps \var{length} bytes from the file
specified by the file descriptor \var{fileno}, and returns a mmap
object.
\var{flags} specifies the nature of the mapping.
\constant{MAP_PRIVATE} creates a private copy-on-write mapping, so
changes to the contents of the mmap object will be private to this
process, and \constant{MAP_SHARED} creates a mapping that's shared
with all other processes mapping the same areas of the file. The
default value is \constant{MAP_SHARED}.
\var{prot}, if specified, gives the desired memory protection; the
two most useful values are \constant{PROT_READ} and
\constant{PROT_WRITE}, to specify that the pages may be read or
written. \var{prot} defaults to \constant{PROT_READ | PROT_WRITE}.
\var{access} may be specified in lieu of \var{flags} and \var{prot}
as an optional keyword parameter. \var{access} accepts one of three
values: \constant{ACCESS_READ}, \constant{ACCESS_WRITE}, or
\constant{ACCESS_COPY} to specify readonly, write-through, or
copy-on-write memory respectively. \var{access} can be used on both
\UNIX{} and Windows. It is an error to specify both \var{flags},
\var{prot} and \var{access}. The initial memory values for all
three access types are taken from the specified file. Assignment to
an \constant{ACCESS_READ} memory map raises a \exception{TypeError}
exception. Assignment to an \constant{ACCESS_WRITE} memory map
affects both memory and the underlying file. Assigment to an
\constant{ACCESS_COPY} memory map affects memory but does not update
the underlying file.
\end{funcdesc}
@ -60,73 +91,80 @@ Memory-mapped file objects support the following methods:
\begin{methoddesc}{close}{}
Close the file. Subsequent calls to other methods of the object
will result in an exception being raised.
Close the file. Subsequent calls to other methods of the object
will result in an exception being raised.
\end{methoddesc}
\begin{methoddesc}{find}{string\optional{, start}}
Returns the lowest index in the object where the substring
\var{string} is found. Returns \code{-1} on failure. \var{start} is
the index at which the search begins, and defaults to zero.
Returns the lowest index in the object where the substring
\var{string} is found. Returns \code{-1} on failure. \var{start}
is the index at which the search begins, and defaults to zero.
\end{methoddesc}
\begin{methoddesc}{flush}{\optional{offset, size}}
Flushes changes made to the in-memory copy of a file back to disk.
Without use of this call there is no guarantee that changes are
written back before the object is destroyed. If \var{offset} and
\var{size} are specified, only changes to the given range of bytes
will be flushed to disk; otherwise, the whole extent of the mapping is
flushed.
Flushes changes made to the in-memory copy of a file back to disk.
Without use of this call there is no guarantee that changes are
written back before the object is destroyed. If \var{offset} and
\var{size} are specified, only changes to the given range of bytes
will be flushed to disk; otherwise, the whole extent of the mapping
is flushed.
\end{methoddesc}
\begin{methoddesc}{move}{\var{dest}, \var{src}, \var{count}}
Copy the \var{count} bytes starting at offset \var{src}
to the destination index \var{dest}.
Copy the \var{count} bytes starting at offset \var{src} to the
destination index \var{dest}. If the mmap was created with
\constant{ACCESS_READ}, then calls to move will throw a
\exception{TypeError} exception.
\end{methoddesc}
\begin{methoddesc}{read}{\var{num}}
Return a string containing up to \var{num} bytes starting from the
current file position; the file position is updated to point after the
bytes that were returned.
Return a string containing up to \var{num} bytes starting from the
current file position; the file position is updated to point after the
bytes that were returned.
\end{methoddesc}
\begin{methoddesc}{read_byte}{}
Returns a string of length 1 containing the character at the current
file position, and advances the file position by 1.
Returns a string of length 1 containing the character at the current
file position, and advances the file position by 1.
\end{methoddesc}
\begin{methoddesc}{readline}{}
Returns a single line, starting at the current file position and up to
the next newline.
Returns a single line, starting at the current file position and up to
the next newline.
\end{methoddesc}
\begin{methoddesc}{resize}{\var{newsize}}
If the mmap was created with \constant{ACCESS_READ} or
\constant{ACCESS_COPY}, resizing the map will throw a \exception{TypeError} exception.
\end{methoddesc}
\begin{methoddesc}{seek}{pos\optional{, whence}}
Set the file's current position.
\var{whence} argument is optional and defaults to \code{0} (absolute
file positioning); other values are \code{1} (seek relative to the
current position) and \code{2} (seek relative to the file's end).
Set the file's current position. \var{whence} argument is optional
and defaults to \code{0} (absolute file positioning); other values
are \code{1} (seek relative to the current position) and \code{2}
(seek relative to the file's end).
\end{methoddesc}
\begin{methoddesc}{size}{}
Return the length of the file, which can be larger than the size
of the memory-mapped area.
Return the length of the file, which can be larger than the size of
the memory-mapped area.
\end{methoddesc}
\begin{methoddesc}{tell}{}
Returns the current position of the file pointer.
Returns the current position of the file pointer.
\end{methoddesc}
\begin{methoddesc}{write}{\var{string}}
Write the bytes in \var{string} into memory at the current position of
the file pointer; the file position is updated to point after the
bytes that were written.
Write the bytes in \var{string} into memory at the current position
of the file pointer; the file position is updated to point after the
bytes that were written. If the mmap was created with
\constant{ACCESS_READ}, then writing to it will throw a
\exception{TypeError} exception.
\end{methoddesc}
\begin{methoddesc}{write_byte}{\var{byte}}
Write the single-character string \var{byte} into memory at the
current position of the file pointer; the file position is advanced by
\code{1}.
Write the single-character string \var{byte} into memory at the
current position of the file pointer; the file position is advanced
by \code{1}.If the mmap was created with \constant{ACCESS_READ},
then writing to it will throw a \exception{TypeError} exception.
\end{methoddesc}

13
Lib/test/output/test_mmap
View File

@ -17,4 +17,17 @@ test_mmap
Try to seek beyond end of mmap...
Try to seek to negative position...
Attempting resize()
Creating 10 byte test data file.
Opening mmap with access=ACCESS_READ
Ensuring that readonly mmap can't be slice assigned.
Ensuring that readonly mmap can't be item assigned.
Ensuring that readonly mmap can't be write() to.
Ensuring that readonly mmap can't be write_byte() to.
Ensuring that readonly mmap can't be resized.
Opening mmap with access=ACCESS_WRITE
Modifying write-through memory map.
Opening mmap with access=ACCESS_COPY
Modifying copy-on-write memory map.
Ensuring copy-on-write maps cannot be resized.
Ensuring invalid access parameter raises exception.
Test passed

138
Lib/test/test_mmap.py
View File

@ -1,4 +1,4 @@
from test_support import verify, TESTFN
from test_support import verify, vereq, TESTFN
import mmap
import os, re
@ -25,15 +25,15 @@ def test_both():
print type(m) # SF bug 128713: segfaulted on Linux
print ' Position of foo:', m.find('foo') / float(PAGESIZE), 'pages'
verify(m.find('foo') == PAGESIZE)
vereq(m.find('foo'), PAGESIZE)
print ' Length of file:', len(m) / float(PAGESIZE), 'pages'
verify(len(m) == 2*PAGESIZE)
vereq(len(m), 2*PAGESIZE)
print ' Contents of byte 0:', repr(m[0])
verify(m[0] == '\0')
vereq(m[0], '\0')
print ' Contents of first 3 bytes:', repr(m[0:3])
verify(m[0:3] == '\0\0\0')
vereq(m[0:3], '\0\0\0')
# Modify the file's content
print "\n Modifying file's content..."
@ -42,11 +42,11 @@ def test_both():
# Check that the modification worked
print ' Contents of byte 0:', repr(m[0])
verify(m[0] == '3')
vereq(m[0], '3')
print ' Contents of first 3 bytes:', repr(m[0:3])
verify(m[0:3] == '3\0\0')
vereq(m[0:3], '3\0\0')
print ' Contents of second page:', repr(m[PAGESIZE-1 : PAGESIZE + 7])
verify(m[PAGESIZE-1 : PAGESIZE + 7] == '\0foobar\0')
vereq(m[PAGESIZE-1 : PAGESIZE + 7], '\0foobar\0')
m.flush()
@ -61,19 +61,19 @@ def test_both():
print ' Regex match on mmap (page start, length of match):',
print start / float(PAGESIZE), length
verify(start == PAGESIZE)
verify(end == PAGESIZE + 6)
vereq(start, PAGESIZE)
vereq(end, PAGESIZE + 6)
# test seeking around (try to overflow the seek implementation)
m.seek(0,0)
print ' Seek to zeroth byte'
verify(m.tell() == 0)
vereq(m.tell(), 0)
m.seek(42,1)
print ' Seek to 42nd byte'
verify(m.tell() == 42)
vereq(m.tell(), 42)
m.seek(0,2)
print ' Seek to last byte'
verify(m.tell() == len(m))
vereq(m.tell(), len(m))
print ' Try to seek to negative position...'
try:
@ -132,6 +132,118 @@ def test_both():
except OSError:
pass
# Test for "access" keyword parameter
try:
mapsize = 10
print " Creating", mapsize, "byte test data file."
open(TESTFN, "wb").write("a"*mapsize)
print " Opening mmap with access=ACCESS_READ"
f = open(TESTFN, "rb")
m = mmap.mmap(f.fileno(), mapsize, access=mmap.ACCESS_READ)
verify(m[:] == 'a'*mapsize, "Readonly memory map data incorrect.")
print " Ensuring that readonly mmap can't be slice assigned."
try:
m[:] = 'b'*mapsize
except TypeError:
pass
else:
verify(0, "Able to write to readonly memory map")
print " Ensuring that readonly mmap can't be item assigned."
try:
m[0] = 'b'
except TypeError:
pass
else:
verify(0, "Able to write to readonly memory map")
print " Ensuring that readonly mmap can't be write() to."
try:
m.seek(0,0)
m.write('abc')
except TypeError:
pass
else:
verify(0, "Able to write to readonly memory map")
print " Ensuring that readonly mmap can't be write_byte() to."
try:
m.seek(0,0)
m.write_byte('d')
except TypeError:
pass
else:
verify(0, "Able to write to readonly memory map")
print " Ensuring that readonly mmap can't be resized."
try:
m.resize(2*mapsize)
except SystemError: # resize is not universally supported
pass
except TypeError:
pass
else:
verify(0, "Able to resize readonly memory map")
del m, f
verify(open(TESTFN, "rb").read() == 'a'*mapsize,
"Readonly memory map data file was modified")
print " Opening mmap with access=ACCESS_WRITE"
f = open(TESTFN, "r+b")
m = mmap.mmap(f.fileno(), mapsize, access=mmap.ACCESS_WRITE)
print " Modifying write-through memory map."
m[:] = 'c'*mapsize
verify(m[:] == 'c'*mapsize,
"Write-through memory map memory not updated properly.")
m.flush()
del m, f
verify(open(TESTFN).read() == 'c'*mapsize,
"Write-through memory map data file not updated properly.")
print " Opening mmap with access=ACCESS_COPY"
f = open(TESTFN, "r+b")
m = mmap.mmap(f.fileno(), mapsize, access=mmap.ACCESS_COPY)
print " Modifying copy-on-write memory map."
m[:] = 'd'*mapsize
verify(m[:] == 'd' * mapsize,
"Copy-on-write memory map data not written correctly.")
m.flush()
verify(open(TESTFN, "rb").read() == 'c'*mapsize,
"Copy-on-write test data file should not be modified.")
try:
print " Ensuring copy-on-write maps cannot be resized."
m.resize(2*mapsize)
except TypeError:
pass
else:
verify(0, "Copy-on-write mmap resize did not raise exception.")
del m, f
try:
print " Ensuring invalid access parameter raises exception."
f = open(TESTFN, "r+b")
m = mmap.mmap(f.fileno(), mapsize, access=4)
except ValueError:
pass
else:
verify(0, "Invalid access code should have raised exception.")
if os.name == "posix":
print " Trying incompatible flags, prot and access parameters."
f=open(TESTFN, "r+b")
try:
m = mmap.mmap(f.fileno(), mapsize, flags=mmap.MAP_PRIVATE,
prot=mmap.PROT_READ, access=mmap.ACCESS_WRITE)
except ValueError:
pass
else:
verify(0, "Incompatible parameters should raise ValueError.")
finally:
try:
os.unlink(TESTFN)
except OSError:
pass
print ' Test passed'
test_both()

9
Misc/NEWS
View File

@ -36,6 +36,13 @@ Core and builtins
Extension modules
- mmap has a new keyword argument, "access", allowing a uniform way for
both Windows and Unix users to create read-only, write-through and
copy-on-write memory mappings. This was previously possible only on
Unix. A new keyword argument was required to support this in a
uniform way because the mmap() signuatures had diverged across
platforms. Thanks to Jay T Miller for repairing this!
- By default, the gc.garbage list now contains only those instances in
unreachable cycles that have __del__ methods; in 2.1 it contained all
instances in unreachable cycles. "Instances" here has been generalized
@ -55,7 +62,7 @@ Extension modules
Library
- tkFileDialog exposes a Directory class and askdirectory
- tkFileDialog exposes a Directory class and askdirectory
convenience function.
- Symbolic group names in regular expressions must be unique. For

233
Modules/mmapmodule.c
View File

@ -29,9 +29,9 @@
static int
my_getpagesize(void)
{
SYSTEM_INFO si;
GetSystemInfo(&si);
return si.dwPageSize;
SYSTEM_INFO si;
GetSystemInfo(&si);
return si.dwPageSize;
}
#endif
@ -49,7 +49,7 @@ my_getpagesize(void)
static int
my_getpagesize(void)
{
return sysconf(_SC_PAGESIZE);
return sysconf(_SC_PAGESIZE);
}
#else
#define my_getpagesize getpagesize
@ -62,6 +62,14 @@ my_getpagesize(void)
static PyObject *mmap_module_error;
typedef enum
{
ACCESS_DEFAULT,
ACCESS_READ,
ACCESS_WRITE,
ACCESS_COPY
} access_mode;
typedef struct {
PyObject_HEAD
char * data;
@ -77,8 +85,11 @@ typedef struct {
#ifdef UNIX
int fd;
#endif
access_mode access;
} mmap_object;
static void
mmap_object_dealloc(mmap_object *m_obj)
{
@ -178,7 +189,7 @@ mmap_read_byte_method(mmap_object *self,
static PyObject *
mmap_read_line_method(mmap_object *self,
PyObject *args)
PyObject *args)
{
char *start = self->data+self->pos;
char *eof = self->data+self->size;
@ -236,11 +247,11 @@ mmap_find_method(mmap_object *self,
char *e = self->data + self->size;
if (start < 0)
start += self->size;
start += self->size;
if (start < 0)
start = 0;
start = 0;
else if ((size_t)start > self->size)
start = self->size;
start = self->size;
p = self->data + start;
while (p < e) {
@ -260,6 +271,26 @@ mmap_find_method(mmap_object *self,
}
}
static int
is_writeable(mmap_object *self)
{
if (self->access != ACCESS_READ)
return 1;
PyErr_Format(PyExc_TypeError, "mmap can't modify a readonly memory map.");
return 0;
}
static int
is_resizeable(mmap_object *self)
{
if ((self->access == ACCESS_WRITE) || (self->access == ACCESS_DEFAULT))
return 1;
PyErr_Format(PyExc_TypeError,
"mmap can't resize a readonly or copy-on-write memory map.");
return 0;
}
static PyObject *
mmap_write_method(mmap_object *self,
PyObject *args)
@ -271,6 +302,9 @@ mmap_write_method(mmap_object *self,
if (!PyArg_ParseTuple (args, "s#:write", &data, &length))
return(NULL);
if (!is_writeable(self))
return NULL;
if ((self->pos + length) > self->size) {
PyErr_SetString (PyExc_ValueError, "data out of range");
return NULL;
@ -291,12 +325,14 @@ mmap_write_byte_method(mmap_object *self,
if (!PyArg_ParseTuple (args, "c:write_byte", &value))
return(NULL);
if (!is_writeable(self))
return NULL;
*(self->data+self->pos) = value;
self->pos += 1;
Py_INCREF (Py_None);
return (Py_None);
}
static PyObject *
mmap_size_method(mmap_object *self,
PyObject *args)
@ -342,7 +378,8 @@ mmap_resize_method(mmap_object *self,
{
unsigned long new_size;
CHECK_VALID(NULL);
if (!PyArg_ParseTuple (args, "l:resize", &new_size)) {
if (!PyArg_ParseTuple (args, "l:resize", &new_size) ||
!is_resizeable(self)) {
return NULL;
#ifdef MS_WIN32
} else {
@ -386,31 +423,31 @@ mmap_resize_method(mmap_object *self,
#ifdef UNIX
#ifndef HAVE_MREMAP
} else {
PyErr_SetString(PyExc_SystemError,
"mmap: resizing not available--no mremap()");
return NULL;
} else {
PyErr_SetString(PyExc_SystemError,
"mmap: resizing not available--no mremap()");
return NULL;
#else
} else {
void *newmap;
} else {
void *newmap;
#ifdef MREMAP_MAYMOVE
newmap = mremap(self->data, self->size, new_size, MREMAP_MAYMOVE);
newmap = mremap(self->data, self->size, new_size, MREMAP_MAYMOVE);
#else
newmap = mremap(self->data, self->size, new_size, 0);
newmap = mremap(self->data, self->size, new_size, 0);
#endif
if (newmap == (void *)-1)
{
PyErr_SetFromErrno(mmap_module_error);
return NULL;
}
self->data = newmap;
self->size = new_size;
Py_INCREF(Py_None);
return Py_None;
if (newmap == (void *)-1)
{
PyErr_SetFromErrno(mmap_module_error);
return NULL;
}
self->data = newmap;
self->size = new_size;
Py_INCREF(Py_None);
return Py_None;
#endif /* HAVE_MREMAP */
#endif /* UNIX */
}
}
}
static PyObject *
@ -491,7 +528,7 @@ mmap_seek_method(mmap_object *self, PyObject *args)
return (Py_None);
}
onoutofrange:
onoutofrange:
PyErr_SetString (PyExc_ValueError, "seek out of range");
return NULL;
}
@ -501,7 +538,8 @@ mmap_move_method(mmap_object *self, PyObject *args)
{
unsigned long dest, src, count;
CHECK_VALID(NULL);
if (!PyArg_ParseTuple (args, "iii:move", &dest, &src, &count)) {
if (!PyArg_ParseTuple (args, "iii:move", &dest, &src, &count) ||
!is_writeable(self)) {
return NULL;
} else {
/* bounds check the values */
@ -561,6 +599,8 @@ mmap_buffer_getwritebuf(mmap_object *self, int index, const void **ptr)
"Accessing non-existent mmap segment");
return -1;
}
if (!is_writeable(self))
return -1;
*ptr = self->data;
return self->size;
}
@ -665,7 +705,7 @@ mmap_ass_slice(mmap_object *self, int ilow, int ihigh, PyObject *v)
if (v == NULL) {
PyErr_SetString(PyExc_TypeError,
"mmap object doesn't support slice deletion");
"mmap object doesn't support slice deletion");
return -1;
}
if (! (PyString_Check(v)) ) {
@ -678,6 +718,8 @@ mmap_ass_slice(mmap_object *self, int ilow, int ihigh, PyObject *v)
"mmap slice assignment is wrong size");
return -1;
}
if (!is_writeable(self))
return -1;
buf = PyString_AsString(v);
memcpy(self->data + ilow, buf, ihigh-ilow);
return 0;
@ -695,14 +737,16 @@ mmap_ass_item(mmap_object *self, int i, PyObject *v)
}
if (v == NULL) {
PyErr_SetString(PyExc_TypeError,
"mmap object doesn't support item deletion");
"mmap object doesn't support item deletion");
return -1;
}
if (! (PyString_Check(v) && PyString_Size(v)==1) ) {
PyErr_SetString(PyExc_IndexError,
"mmap assignment must be single-character string");
"mmap assignment must be single-character string");
return -1;
}
if (!is_writeable(self))
return -1;
buf = PyString_AsString(v);
self->data[i] = buf[0];
return 0;
@ -792,18 +836,18 @@ _GetMapSize(PyObject *o)
}
else {
PyErr_SetString(PyExc_TypeError,
"map size must be an integral value");
"map size must be an integral value");
return -1;
}
onnegoverflow:
onnegoverflow:
PyErr_SetString(PyExc_OverflowError,
"memory mapped size must be positive");
"memory mapped size must be positive");
return -1;
onposoverflow:
onposoverflow:
PyErr_SetString(PyExc_OverflowError,
"memory mapped size is too large (limited by C int)");
"memory mapped size is too large (limited by C int)");
return -1;
}
@ -815,16 +859,42 @@ new_mmap_object(PyObject *self, PyObject *args, PyObject *kwdict)
PyObject *map_size_obj = NULL;
int map_size;
int fd, flags = MAP_SHARED, prot = PROT_WRITE | PROT_READ;
char *keywords[] = {"file", "size", "flags", "prot", NULL};
access_mode access = ACCESS_DEFAULT;
char *keywords[] = {"fileno", "length",
"flags", "prot",
"access", NULL};
if (!PyArg_ParseTupleAndKeywords(args, kwdict,
"iO|ii", keywords,
&fd, &map_size_obj, &flags, &prot)
)
if (!PyArg_ParseTupleAndKeywords(args, kwdict, "iO|iii", keywords,
&fd, &map_size_obj, &flags, &prot, &access))
return NULL;
map_size = _GetMapSize(map_size_obj);
if (map_size < 0)
return NULL;
if ((access != ACCESS_DEFAULT) &&
((flags != MAP_SHARED) || ( prot != (PROT_WRITE | PROT_READ))))
return PyErr_Format(PyExc_ValueError,
"mmap can't specify both access and flags, prot.");
switch(access) {
case ACCESS_READ:
flags = MAP_SHARED;
prot = PROT_READ;
break;
case ACCESS_WRITE:
flags = MAP_SHARED;
prot = PROT_READ | PROT_WRITE;
break;
case ACCESS_COPY:
flags = MAP_PRIVATE;
prot = PROT_READ | PROT_WRITE;
break;
case ACCESS_DEFAULT:
/* use the specified or default values of flags and prot */
break;
default:
return PyErr_Format(PyExc_ValueError,
"mmap invalid access parameter.");
}
m_obj = PyObject_New (mmap_object, &mmap_object_type);
if (m_obj == NULL) {return NULL;}
@ -834,37 +904,57 @@ new_mmap_object(PyObject *self, PyObject *args, PyObject *kwdict)
m_obj->data = mmap(NULL, map_size,
prot, flags,
fd, 0);
if (m_obj->data == (char *)-1)
{
if (m_obj->data == (char *)-1) {
Py_DECREF(m_obj);
PyErr_SetFromErrno(mmap_module_error);
return NULL;
}
m_obj->access = access;
return (PyObject *)m_obj;
}
#endif /* UNIX */
#ifdef MS_WIN32
static PyObject *
new_mmap_object(PyObject *self, PyObject *args)
new_mmap_object(PyObject *self, PyObject *args, PyObject *kwdict)
{
mmap_object *m_obj;
PyObject *map_size_obj = NULL;
int map_size;
char *tagname = "";
DWORD dwErr = 0;
int fileno;
HANDLE fh = 0;
access_mode access = ACCESS_DEFAULT;
DWORD flProtect, dwDesiredAccess;
char *keywords[] = { "fileno", "length",
"tagname",
"access", NULL };
if (!PyArg_ParseTuple(args,
"iO|z",
&fileno,
&map_size_obj,
&tagname)
)
if (!PyArg_ParseTupleAndKeywords(args, kwdict, "iO|zi", keywords,
&fileno, &map_size_obj,
&tagname, &access)) {
return NULL;
}
switch(access) {
case ACCESS_READ:
flProtect = PAGE_READONLY;
dwDesiredAccess = FILE_MAP_READ;
break;
case ACCESS_DEFAULT: case ACCESS_WRITE:
flProtect = PAGE_READWRITE;
dwDesiredAccess = FILE_MAP_WRITE;
break;
case ACCESS_COPY:
flProtect = PAGE_WRITECOPY;
dwDesiredAccess = FILE_MAP_COPY;
break;
default:
return PyErr_Format(PyExc_ValueError,
"mmap invalid access parameter.");
}
map_size = _GetMapSize(map_size_obj);
if (map_size < 0)
return NULL;
@ -873,8 +963,8 @@ new_mmap_object(PyObject *self, PyObject *args)
if (fileno != 0) {
fh = (HANDLE)_get_osfhandle(fileno);
if (fh==(HANDLE)-1) {
PyErr_SetFromErrno(mmap_module_error);
return NULL;
PyErr_SetFromErrno(mmap_module_error);
return NULL;
}
/* Win9x appears to need us seeked to zero */
fseek(&_iob[fileno], 0, SEEK_SET);
@ -894,13 +984,13 @@ new_mmap_object(PyObject *self, PyObject *args)
/* It is necessary to duplicate the handle, so the
Python code can close it on us */
if (!DuplicateHandle(
GetCurrentProcess(), /* source process handle */
fh, /* handle to be duplicated */
GetCurrentProcess(), /* target proc handle */
(LPHANDLE)&m_obj->file_handle, /* result */
0, /* access - ignored due to options value */
FALSE, /* inherited by child processes? */
DUPLICATE_SAME_ACCESS)) { /* options */
GetCurrentProcess(), /* source process handle */
fh, /* handle to be duplicated */
GetCurrentProcess(), /* target proc handle */
(LPHANDLE)&m_obj->file_handle, /* result */
0, /* access - ignored due to options value */
FALSE, /* inherited by child processes? */
DUPLICATE_SAME_ACCESS)) { /* options */
dwErr = GetLastError();
Py_DECREF(m_obj);
PyErr_SetFromWindowsErr(dwErr);
@ -932,22 +1022,23 @@ new_mmap_object(PyObject *self, PyObject *args)
else
m_obj->tagname = NULL;
m_obj->access = access;
m_obj->map_handle = CreateFileMapping (m_obj->file_handle,
NULL,
PAGE_READWRITE,
flProtect,
0,
m_obj->size,
m_obj->tagname);
if (m_obj->map_handle != NULL) {
m_obj->data = (char *) MapViewOfFile (m_obj->map_handle,
FILE_MAP_WRITE,
dwDesiredAccess,
0,
0,
0);
if (m_obj->data != NULL) {
return ((PyObject *) m_obj);
} else {
dwErr = GetLastError();
dwErr = GetLastError();
}
} else {
dwErr = GetLastError();
@ -966,7 +1057,7 @@ static struct PyMethodDef mmap_functions[] = {
};
DL_EXPORT(void)
initmmap(void)
initmmap(void)
{
PyObject *dict, *module;
@ -1011,5 +1102,11 @@ initmmap(void)
PyDict_SetItemString (dict, "PAGESIZE",
PyInt_FromLong( (long)my_getpagesize() ) );
}
PyDict_SetItemString (dict, "ACCESS_READ",
PyInt_FromLong(ACCESS_READ));
PyDict_SetItemString (dict, "ACCESS_WRITE",
PyInt_FromLong(ACCESS_WRITE));
PyDict_SetItemString (dict, "ACCESS_COPY",
PyInt_FromLong(ACCESS_COPY));
}