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/ Author: Sam Rushing <rushing@nightmare.com>

/ Hacked for Unix by AMK

/ $Id$

/ Modified to support mmap with offset - to map a 'window' of a file

/ Author: Yotam Medini yotamm@mellanox.co.il

/ mmapmodule.cpp -- map a view of a file into memory

/ todo: need permission flags, perhaps a 'chsize' analog

/ not all functions check range yet!!!

/ This version of mmapmodule.c has been changed significantly

/ from the original mmapfile.c on which it was based.

/ The original version of mmapfile is maintained by Sam at

/ ftp://squirl.nightmare.com/pub/python/python-ext.

#ifndef Py_BUILD_CORE_BUILTIN

# define Py_BUILD_CORE_MODULE 1

#endif

#include <Python.h>

#include "pycore_abstract.h" // _Py_convert_optional_to_ssize_t()

#include "pycore_bytesobject.h" // _PyBytes_Find()

#include "pycore_fileutils.h" // _Py_stat_struct

#include "pycore_mmap.h" // _PyAnnotateMemoryMap()

#include "pycore_weakref.h" // FT_CLEAR_WEAKREFS()

#include <stddef.h> // offsetof()

#ifndef MS_WINDOWS

# include <unistd.h> // close()

#endif

#ifndef MS_WINDOWS

#define UNIX

# ifdef HAVE_FCNTL_H

# include <fcntl.h>

# endif /* HAVE_FCNTL_H */

#endif

#ifdef MS_WINDOWS

#include <windows.h>

#include <ntsecapi.h> // LsaNtStatusToWinError

static int

my_getpagesize(void)

{

SYSTEM_INFO si;

GetSystemInfo(&si);

return si.dwPageSize;

}

static int

my_getallocationgranularity (void)

{

SYSTEM_INFO si;

GetSystemInfo(&si);

return si.dwAllocationGranularity;

}

#endif

#ifdef UNIX

#include <sys/mman.h>

#include <sys/stat.h>

#if defined(HAVE_SYSCONF) && defined(_SC_PAGESIZE)

static int

my_getpagesize(void)

{

return sysconf(_SC_PAGESIZE);

}

#define my_getallocationgranularity my_getpagesize

#else

#define my_getpagesize getpagesize

#endif

#endif /* UNIX */

#include <string.h>

#ifdef HAVE_SYS_TYPES_H

#include <sys/types.h>

#endif /* HAVE_SYS_TYPES_H */

/* Prefer MAP_ANONYMOUS since MAP_ANON is deprecated according to man page. */

#if !defined(MAP_ANONYMOUS) && defined(MAP_ANON)

# define MAP_ANONYMOUS MAP_ANON

#endif

/*[clinic input]

module mmap

class mmap.mmap "mmap_object *" ""

[clinic start generated code]*/

/*[clinic end generated code: output=da39a3ee5e6b4b0d input=82a9f8a529905b9b]*/

typedef enum

{

ACCESS_DEFAULT,

ACCESS_READ,

ACCESS_WRITE,

ACCESS_COPY

} access_mode;

typedef struct {

PyObject_HEAD

char * data;

Py_ssize_t size;

Py_ssize_t pos; /* relative to offset */

#ifdef MS_WINDOWS

long long offset;

#else

off_t offset;

#endif

Py_ssize_t exports;

#ifdef MS_WINDOWS

HANDLE map_handle;

HANDLE file_handle;

wchar_t * tagname;

#endif

#ifdef UNIX

int fd;

int flags;

#endif

PyObject *weakreflist;

access_mode access;

_Bool trackfd;

} mmap_object;

#define mmap_object_CAST(op) ((mmap_object *)(op))

#include "clinic/mmapmodule.c.h"

/* Return a Py_ssize_t from the object arg. This conversion logic is similar

to what AC uses for `Py_ssize_t` arguments.

Returns -1 on error. Use PyErr_Occurred() to disambiguate.

static Py_ssize_t

_As_Py_ssize_t(PyObject *arg) {

assert(arg != NULL);

Py_ssize_t ival = -1;

PyObject *iobj = _PyNumber_Index(arg);

if (iobj != NULL) {

ival = PyLong_AsSsize_t(iobj);

Py_DECREF(iobj);

}

return ival;

}

static void

mmap_object_dealloc(PyObject *op)

{

mmap_object *m_obj = mmap_object_CAST(op);

PyTypeObject *tp = Py_TYPE(m_obj);

PyObject_GC_UnTrack(m_obj);

#ifdef MS_WINDOWS

Py_BEGIN_ALLOW_THREADS

if (m_obj->data != NULL)

UnmapViewOfFile (m_obj->data);

if (m_obj->map_handle != NULL)

CloseHandle (m_obj->map_handle);

if (m_obj->file_handle != INVALID_HANDLE_VALUE)

CloseHandle (m_obj->file_handle);

Py_END_ALLOW_THREADS

if (m_obj->tagname)

PyMem_Free(m_obj->tagname);

#endif /* MS_WINDOWS */

#ifdef UNIX

Py_BEGIN_ALLOW_THREADS

if (m_obj->fd >= 0)

(void) close(m_obj->fd);

if (m_obj->data!=NULL) {

munmap(m_obj->data, m_obj->size);

}

Py_END_ALLOW_THREADS

#endif /* UNIX */

FT_CLEAR_WEAKREFS(op, m_obj->weakreflist);

tp->tp_free(m_obj);

Py_DECREF(tp);

}

/*[clinic input]

@critical_section

mmap.mmap.close

[clinic start generated code]*/

static PyObject *

mmap_mmap_close_impl(mmap_object *self)

/*[clinic end generated code: output=a1ae0c727546f78d input=25020035f047eae1]*/

{

if (self->exports > 0) {

PyErr_SetString(PyExc_BufferError, "cannot close "\

"exported pointers exist");

return NULL;

}

#ifdef MS_WINDOWS

/* For each resource we maintain, we need to check

the value is valid, and if so, free the resource

and set the member value to an invalid value so

the dealloc does not attempt to resource clearing

again.

TODO - should we check for errors in the close operations???

HANDLE map_handle = self->map_handle;

HANDLE file_handle = self->file_handle;

char *data = self->data;

self->map_handle = NULL;

self->file_handle = INVALID_HANDLE_VALUE;

self->data = NULL;

Py_BEGIN_ALLOW_THREADS

if (data != NULL) {

UnmapViewOfFile(data);

}

if (map_handle != NULL) {

CloseHandle(map_handle);

}

if (file_handle != INVALID_HANDLE_VALUE) {

CloseHandle(file_handle);

}

Py_END_ALLOW_THREADS

#endif /* MS_WINDOWS */

#ifdef UNIX

int fd = self->fd;

char *data = self->data;

self->fd = -1;

self->data = NULL;

Py_BEGIN_ALLOW_THREADS

if (0 <= fd)

(void) close(fd);

if (data != NULL) {

munmap(data, self->size);

}

Py_END_ALLOW_THREADS

#endif

Py_RETURN_NONE;

}

#ifdef MS_WINDOWS

#define CHECK_VALID(err) \

do { \

if (self->map_handle == NULL) { \

PyErr_SetString(PyExc_ValueError, "mmap closed or invalid"); \

return err; \

} \

} while (0)

#define CHECK_VALID_OR_RELEASE(err, buffer) \

do { \

if (self->map_handle == NULL) { \

PyErr_SetString(PyExc_ValueError, "mmap closed or invalid"); \

PyBuffer_Release(&(buffer)); \

return (err); \

} \

} while (0)

#endif /* MS_WINDOWS */

#ifdef UNIX

#define CHECK_VALID(err) \

do { \

if (self->data == NULL) { \

PyErr_SetString(PyExc_ValueError, "mmap closed or invalid"); \

return err; \

} \

} while (0)

#define CHECK_VALID_OR_RELEASE(err, buffer) \

do { \

if (self->data == NULL) { \

PyErr_SetString(PyExc_ValueError, "mmap closed or invalid"); \

PyBuffer_Release(&(buffer)); \

return (err); \

} \

} while (0)

#endif /* UNIX */

#if defined(MS_WINDOWS) && !defined(DONT_USE_SEH)

static DWORD

filter_page_exception(EXCEPTION_POINTERS *ptrs, EXCEPTION_RECORD *record)

{

*record = *ptrs->ExceptionRecord;

if (record->ExceptionCode == EXCEPTION_IN_PAGE_ERROR ||

record->ExceptionCode == EXCEPTION_ACCESS_VIOLATION)

{

return EXCEPTION_EXECUTE_HANDLER;

}

return EXCEPTION_CONTINUE_SEARCH;

}

static DWORD

filter_page_exception_method(mmap_object *self, EXCEPTION_POINTERS *ptrs,

EXCEPTION_RECORD *record)

{

*record = *ptrs->ExceptionRecord;

if (record->ExceptionCode == EXCEPTION_IN_PAGE_ERROR ||

record->ExceptionCode == EXCEPTION_ACCESS_VIOLATION)

{

ULONG_PTR address = record->ExceptionInformation[1];

if (address >= (ULONG_PTR) self->data &&

address < (ULONG_PTR) self->data + (ULONG_PTR) self->size)

{

return EXCEPTION_EXECUTE_HANDLER;

}

return EXCEPTION_CONTINUE_SEARCH;

}

static void

_PyErr_SetFromNTSTATUS(ULONG status)

{

#if defined(MS_WINDOWS_DESKTOP) || defined(MS_WINDOWS_SYSTEM)

PyErr_SetFromWindowsErr(LsaNtStatusToWinError((NTSTATUS)status));

#else

if (status & 0x80000000) {

// HRESULT-shaped codes are supported by PyErr_SetFromWindowsErr

PyErr_SetFromWindowsErr((int)status);

}

else {

// No mapping for NTSTATUS values, so just return it for diagnostic purposes

// If we provide it as winerror it could incorrectly change the type of the exception.

PyErr_Format(PyExc_OSError, "Operating system error NTSTATUS=0x%08lX", status);

}

#endif

}

#endif

#if defined(MS_WINDOWS_DESKTOP) && !defined(DONT_USE_SEH)

#define HANDLE_INVALID_MEM(sourcecode) \

do { \

EXCEPTION_RECORD record; \

__try { \

sourcecode \

} \

__except (filter_page_exception(GetExceptionInformation(), &record)) { \

assert(record.ExceptionCode == EXCEPTION_IN_PAGE_ERROR || \

record.ExceptionCode == EXCEPTION_ACCESS_VIOLATION); \

if (record.ExceptionCode == EXCEPTION_IN_PAGE_ERROR) { \

_PyErr_SetFromNTSTATUS((ULONG)record.ExceptionInformation[2]); \

} \

else if (record.ExceptionCode == EXCEPTION_ACCESS_VIOLATION) { \

PyErr_SetFromWindowsErr(ERROR_NOACCESS); \

} \

return -1; \

} \

} while (0)

#else

#define HANDLE_INVALID_MEM(sourcecode) \

do { \

sourcecode \

} while (0)

#endif

#if defined(MS_WINDOWS_DESKTOP) && !defined(DONT_USE_SEH)

#define HANDLE_INVALID_MEM_METHOD(self, sourcecode) \

do { \

EXCEPTION_RECORD record; \

__try { \

sourcecode \

} \

__except (filter_page_exception_method(self, GetExceptionInformation(), \

&record)) { \

assert(record.ExceptionCode == EXCEPTION_IN_PAGE_ERROR || \

record.ExceptionCode == EXCEPTION_ACCESS_VIOLATION); \

if (record.ExceptionCode == EXCEPTION_IN_PAGE_ERROR) { \

_PyErr_SetFromNTSTATUS((ULONG)record.ExceptionInformation[2]); \

} \

else if (record.ExceptionCode == EXCEPTION_ACCESS_VIOLATION) { \

PyErr_SetFromWindowsErr(ERROR_NOACCESS); \

} \

return -1; \

} \

} while (0)

#else

#define HANDLE_INVALID_MEM_METHOD(self, sourcecode) \

do { \

sourcecode \

} while (0)

#endif

int

safe_memcpy(void *dest, const void *src, size_t count)

{

HANDLE_INVALID_MEM(

memcpy(dest, src, count);

);

return 0;

}

int

safe_byte_copy(char *dest, const char *src)

{

HANDLE_INVALID_MEM(

*dest = *src;

);

return 0;

}

int

safe_memchr(char **out, const void *ptr, int ch, size_t count)

{

HANDLE_INVALID_MEM(

*out = (char *) memchr(ptr, ch, count);

);

return 0;

}

int

safe_memmove(void *dest, const void *src, size_t count)

{

HANDLE_INVALID_MEM(

memmove(dest, src, count);

);

return 0;

}

int

safe_copy_from_slice(char *dest, const char *src, Py_ssize_t start,

Py_ssize_t step, Py_ssize_t slicelen)

{

HANDLE_INVALID_MEM(

size_t cur;

Py_ssize_t i;

for (cur = start, i = 0; i < slicelen; cur += step, i++) {

dest[cur] = src[i];

}

);

return 0;

}

int

safe_copy_to_slice(char *dest, const char *src, Py_ssize_t start,

Py_ssize_t step, Py_ssize_t slicelen)

{

HANDLE_INVALID_MEM(

size_t cur;

Py_ssize_t i;

for (cur = start, i = 0; i < slicelen; cur += step, i++) {

dest[i] = src[cur];

}

);

return 0;

}

int

_safe_PyBytes_Find(Py_ssize_t *out, mmap_object *self, const char *haystack,

Py_ssize_t len_haystack, const char *needle,

Py_ssize_t len_needle, Py_ssize_t offset)

{

HANDLE_INVALID_MEM_METHOD(self,

*out = _PyBytes_Find(haystack, len_haystack, needle, len_needle, offset);

);

return 0;

}

int

_safe_PyBytes_ReverseFind(Py_ssize_t *out, mmap_object *self,

const char *haystack, Py_ssize_t len_haystack,

const char *needle, Py_ssize_t len_needle,

Py_ssize_t offset)

{

HANDLE_INVALID_MEM_METHOD(self,

*out = _PyBytes_ReverseFind(haystack, len_haystack, needle, len_needle,

offset);

);

return 0;

}

PyObject *

_safe_PyBytes_FromStringAndSize(char *start, size_t num_bytes)

{

if (num_bytes == 1) {

char dest;

if (safe_byte_copy(&dest, start) < 0) {

return NULL;

}

else {

return PyBytes_FromStringAndSize(&dest, 1);

}

else {

PyBytesWriter *writer = PyBytesWriter_Create(num_bytes);

if (writer == NULL) {

return NULL;

}

if (safe_memcpy(PyBytesWriter_GetData(writer), start, num_bytes) < 0) {

PyBytesWriter_Discard(writer);

return NULL;

}

return PyBytesWriter_Finish(writer);

}

/*[clinic input]

@critical_section

mmap.mmap.read_byte

[clinic start generated code]*/

static PyObject *

mmap_mmap_read_byte_impl(mmap_object *self)

/*[clinic end generated code: output=d931da1319f3869b input=5b8c6a904bdddda9]*/

{

CHECK_VALID(NULL);

if (self->pos >= self->size) {

PyErr_SetString(PyExc_ValueError, "read byte out of range");

return NULL;

}

char dest;

if (safe_byte_copy(&dest, self->data + self->pos) < 0) {

return NULL;

}

self->pos++;

return PyLong_FromLong((unsigned char) dest);

}

/*[clinic input]

@critical_section

mmap.mmap.readline

[clinic start generated code]*/

static PyObject *

mmap_mmap_readline_impl(mmap_object *self)

/*[clinic end generated code: output=b9d2bf9999283311 input=2c4efd1d06e1cdd1]*/

{

Py_ssize_t remaining;

char *start, *eol;

CHECK_VALID(NULL);

remaining = (self->pos < self->size) ? self->size - self->pos : 0;

if (!remaining)

return Py_GetConstant(Py_CONSTANT_EMPTY_BYTES);

start = self->data + self->pos;

if (safe_memchr(&eol, start, '\n', remaining) < 0) {

return NULL;

}

if (!eol)

eol = self->data + self->size;

else

++eol; /* advance past newline */

PyObject *result = _safe_PyBytes_FromStringAndSize(start, eol - start);

if (result != NULL) {

self->pos += (eol - start);

}

return result;

}

/*[clinic input]

@critical_section

mmap.mmap.read

n as num_bytes: object(converter='_Py_convert_optional_to_ssize_t', type='Py_ssize_t', c_default='PY_SSIZE_T_MAX') = None

[clinic start generated code]*/

static PyObject *

mmap_mmap_read_impl(mmap_object *self, Py_ssize_t num_bytes)

/*[clinic end generated code: output=3b4d4f3704ed0969 input=8f97f361d435e357]*/

{

Py_ssize_t remaining;

CHECK_VALID(NULL);

/* silently 'adjust' out-of-range requests */

remaining = (self->pos < self->size) ? self->size - self->pos : 0;

if (num_bytes < 0 || num_bytes > remaining)

num_bytes = remaining;

PyObject *result = _safe_PyBytes_FromStringAndSize(self->data + self->pos,

num_bytes);

if (result != NULL) {

self->pos += num_bytes;

}

return result;

}

static PyObject *

mmap_gfind_lock_held(mmap_object *self, Py_buffer *view, PyObject *start_obj,

PyObject *end_obj, int reverse)

{

Py_ssize_t start = self->pos;

Py_ssize_t end = self->size;

CHECK_VALID(NULL);

if (start_obj != Py_None) {

start = _As_Py_ssize_t(start_obj);

if (start == -1 && PyErr_Occurred()) {

return NULL;

}

if (end_obj != Py_None) {

end = _As_Py_ssize_t(end_obj);

if (end == -1 && PyErr_Occurred()) {

return NULL;

}

if (start < 0)

start += self->size;

if (start < 0)

start = 0;

if (end < 0)

end += self->size;

if (end < 0)

end = 0;

else if (end > self->size)

end = self->size;

Py_ssize_t index;

PyObject *result;

CHECK_VALID(NULL);

if (end < start) {

result = PyLong_FromSsize_t(-1);

}

else if (reverse) {

assert(0 <= start && start <= end && end <= self->size);

if (_safe_PyBytes_ReverseFind(&index, self,

self->data + start, end - start,

view->buf, view->len, start) < 0)

{

result = NULL;

}

else {

result = PyLong_FromSsize_t(index);

}

else {

assert(0 <= start && start <= end && end <= self->size);

if (_safe_PyBytes_Find(&index, self,

self->data + start, end - start,

view->buf, view->len, start) < 0)

{

result = NULL;

}

else {

result = PyLong_FromSsize_t(index);

}

return result;

}

/*[clinic input]

@critical_section

mmap.mmap.find

view: Py_buffer

start: object = None

end: object = None

[clinic start generated code]*/

static PyObject *

mmap_mmap_find_impl(mmap_object *self, Py_buffer *view, PyObject *start,

PyObject *end)

/*[clinic end generated code: output=ef8878a322f00192 input=0135504494b52c2b]*/

{

return mmap_gfind_lock_held(self, view, start, end, 0);

}

/*[clinic input]

@critical_section

mmap.mmap.rfind = mmap.mmap.find

[clinic start generated code]*/

static PyObject *

mmap_mmap_rfind_impl(mmap_object *self, Py_buffer *view, PyObject *start,

PyObject *end)

/*[clinic end generated code: output=73b918940d67c2b8 input=8aecdd1f70c06c62]*/

{

return mmap_gfind_lock_held(self, view, start, end, 1);

}

static int

is_writable(mmap_object *self)

{

if (self->access != ACCESS_READ)

return 1;

PyErr_Format(PyExc_TypeError, "mmap can't modify a readonly memory map.");

return 0;

}

#if defined(MS_WINDOWS) || defined(HAVE_MREMAP)

static int

is_resizeable(mmap_object *self)

{

if (self->exports > 0) {

PyErr_SetString(PyExc_BufferError,

"mmap can't resize with extant buffers exported.");

return 0;

}

if (!self->trackfd) {

PyErr_SetString(PyExc_ValueError,

"mmap can't resize with trackfd=False.");

return 0;

}

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;

}

#endif /* MS_WINDOWS || HAVE_MREMAP */

/*[clinic input]

@critical_section

mmap.mmap.write

bytes as data: Py_buffer

[clinic start generated code]*/

static PyObject *

mmap_mmap_write_impl(mmap_object *self, Py_buffer *data)

/*[clinic end generated code: output=9e97063efb6fb27b input=3f16fa79aa89d6f7]*/

{

CHECK_VALID(NULL);

if (!is_writable(self)) {

return NULL;

}

if (self->pos > self->size || self->size - self->pos < data->len) {

PyErr_SetString(PyExc_ValueError, "data out of range");

return NULL;

}

CHECK_VALID(NULL);

PyObject *result;

if (safe_memcpy(self->data + self->pos, data->buf, data->len) < 0) {

result = NULL;

}

else {

self->pos += data->len;

result = PyLong_FromSsize_t(data->len);

}

return result;

}

/*[clinic input]

@critical_section

mmap.mmap.write_byte

byte as value: unsigned_char

[clinic start generated code]*/

static PyObject *

mmap_mmap_write_byte_impl(mmap_object *self, unsigned char value)

/*[clinic end generated code: output=aa11adada9b17510 input=32740bfa174f0991]*/

{

CHECK_VALID(NULL);

if (!is_writable(self))

return NULL;

CHECK_VALID(NULL);

if (self->pos >= self->size) {

PyErr_SetString(PyExc_ValueError, "write byte out of range");

return NULL;

}

if (safe_byte_copy(self->data + self->pos, (const char*)&value) < 0) {

return NULL;

}

self->pos++;

Py_RETURN_NONE;

}

/*[clinic input]

@critical_section

mmap.mmap.size

[clinic start generated code]*/

static PyObject *

mmap_mmap_size_impl(mmap_object *self)

/*[clinic end generated code: output=c177e65e83a648ff input=f69c072efd2e1595]*/

{

CHECK_VALID(NULL);

#ifdef MS_WINDOWS

if (self->file_handle != INVALID_HANDLE_VALUE) {

LARGE_INTEGER size;

if (!GetFileSizeEx(self->file_handle, &size)) {

DWORD error = GetLastError();

return PyErr_SetFromWindowsErr(error);

}

return PyLong_FromLongLong(size.QuadPart);

}

#endif /* MS_WINDOWS */

#ifdef UNIX

if (self->fd != -1) {

struct _Py_stat_struct status;

if (_Py_fstat(self->fd, &status) == -1)

return NULL;

#ifdef HAVE_LARGEFILE_SUPPORT

return PyLong_FromLongLong(status.st_size);

#else

return PyLong_FromLong(status.st_size);

#endif

}

#endif /* UNIX */

else if (self->trackfd) {

return PyLong_FromSsize_t(self->size);

}

else {

PyErr_SetString(PyExc_ValueError,

"can't get size with trackfd=False");

return NULL;

}

/* This assumes that you want the entire file mapped,

/ and when recreating the map will make the new file

/ have the new size

/ Is this really necessary? This could easily be done

/ from python by just closing and re-opening with the

/ new size?

#if defined(MS_WINDOWS) || defined(HAVE_MREMAP)

/*[clinic input]

@critical_section

mmap.mmap.resize

newsize as new_size: Py_ssize_t

[clinic start generated code]*/

static PyObject *

mmap_mmap_resize_impl(mmap_object *self, Py_ssize_t new_size)

/*[clinic end generated code: output=6f262537ce9c2dcc input=b6b5dee52a41b79f]*/

{

CHECK_VALID(NULL);

if (!is_resizeable(self)) {

return NULL;

}

if (new_size < 0 || PY_SSIZE_T_MAX - new_size < self->offset) {

PyErr_SetString(PyExc_ValueError, "new size out of range");

return NULL;

}

{

#ifdef MS_WINDOWS

DWORD error = 0, file_resize_error = 0;

char* old_data = self->data;

LARGE_INTEGER offset, max_size;

offset.QuadPart = self->offset;

max_size.QuadPart = self->offset + new_size;

/* close the file mapping */

CloseHandle(self->map_handle);

/* if the file mapping still exists, it cannot be resized. */

if (self->tagname) {

self->map_handle = OpenFileMappingW(FILE_MAP_WRITE, FALSE,

self->tagname);

if (self->map_handle) {

PyErr_SetFromWindowsErr(ERROR_USER_MAPPED_FILE);

return NULL;

}

} else {

self->map_handle = NULL;

}

/* if it's not the paging file, unmap the view and resize the file */

if (self->file_handle != INVALID_HANDLE_VALUE) {

if (!UnmapViewOfFile(self->data)) {

return PyErr_SetFromWindowsErr(GetLastError());

};

self->data = NULL;

/* resize the file */

if (!SetFilePointerEx(self->file_handle, max_size, NULL,

FILE_BEGIN) ||

!SetEndOfFile(self->file_handle)) {

/* resizing failed. try to remap the file */

file_resize_error = GetLastError();

max_size.QuadPart = self->size;

new_size = self->size;

}

/* create a new file mapping and map a new view */

/* FIXME: call CreateFileMappingW with wchar_t tagname */

self->map_handle = CreateFileMappingW(

self->file_handle,

NULL,

PAGE_READWRITE,

max_size.HighPart,

max_size.LowPart,

self->tagname);

error = GetLastError();

/* ERROR_ALREADY_EXISTS implies that between our closing the handle above and

calling CreateFileMapping here, someone's created a different mapping with

the same name. There's nothing we can usefully do so we invalidate our

mapping and error out.

if (error == ERROR_ALREADY_EXISTS) {

CloseHandle(self->map_handle);

self->map_handle = NULL;

}

else if (self->map_handle != NULL) {

self->data = MapViewOfFile(self->map_handle,

FILE_MAP_WRITE,

offset.HighPart,

offset.LowPart,

new_size);

if (self->data != NULL) {

/* copy the old view if using the paging file */

if (self->file_handle == INVALID_HANDLE_VALUE) {

memcpy(self->data, old_data,

self->size < new_size ? self->size : new_size);

if (!UnmapViewOfFile(old_data)) {

error = GetLastError();

}

self->size = new_size;

}

else {

error = GetLastError();

CloseHandle(self->map_handle);

self->map_handle = NULL;

}

if (error) {

return PyErr_SetFromWindowsErr(error);

}

/* It's possible for a resize to fail, typically because another mapping

is still held against the same underlying file. Even if nothing has

failed -- ie we're still returning a valid file mapping -- raise the

error as an exception as the resize won't have happened

if (file_resize_error) {

PyErr_SetFromWindowsErr(file_resize_error);

return NULL;

}

Py_RETURN_NONE;

#endif /* MS_WINDOWS */

#ifdef UNIX

void *newmap;

#if defined(__linux__) || defined(__NetBSD__)

// Linux mremap() refuses to grow a shared anonymous mapping, and

// NetBSD mremap() returns a mapping whose grown region is not backed,

// so accessing it crashes. Reject it here in both cases.

if (self->fd == -1 && !(self->flags & MAP_PRIVATE) && new_size > self->size) {

PyErr_Format(PyExc_ValueError,

"mmap: can't expand a shared anonymous mapping");

return NULL;

}

#endif

if (self->fd != -1 && ftruncate(self->fd, self->offset + new_size) == -1) {

PyErr_SetFromErrno(PyExc_OSError);

return NULL;

}

#ifdef MREMAP_MAYMOVE

newmap = mremap(self->data, self->size, new_size, MREMAP_MAYMOVE);

#else

#if defined(__NetBSD__)

newmap = mremap(self->data, self->size, self->data, new_size, 0);

#else

newmap = mremap(self->data, self->size, new_size, 0);

#endif /* __NetBSD__ */

#endif

if (newmap == (void *)-1)

{

PyErr_SetFromErrno(PyExc_OSError);

return NULL;

}

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