cpython/Modules/_io/fileio.c at 3.3 · python/cpython · GitHub

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/* Author: Daniel Stutzbach */

#define PY_SSIZE_T_CLEAN

#include "Python.h"

#include "structmember.h"

#ifdef HAVE_SYS_TYPES_H

#include <sys/types.h>

#endif

#ifdef HAVE_SYS_STAT_H

#include <sys/stat.h>

#endif

#ifdef HAVE_FCNTL_H

#include <fcntl.h>

#endif

#include <stddef.h> /* For offsetof */

#include "_iomodule.h"

* Known likely problems:

* - Files larger then 2**32-1

* - Files with unicode filenames

* - Passing numbers greater than 2**32-1 when an integer is expected

* - Making it work on Windows and other oddball platforms

* To Do:

* - autoconfify header file inclusion

#ifdef MS_WINDOWS

/* can simulate truncate with Win32 API functions; see file_truncate */

#define HAVE_FTRUNCATE

#define WIN32_LEAN_AND_MEAN

#include <windows.h>

#endif

#if BUFSIZ < (8*1024)

#define SMALLCHUNK (8*1024)

#elif (BUFSIZ >= (2 << 25))

#error "unreasonable BUFSIZ > 64MB defined"

#else

#define SMALLCHUNK BUFSIZ

#endif

typedef struct {

PyObject_HEAD

int fd;

unsigned int created : 1;

unsigned int readable : 1;

unsigned int writable : 1;

unsigned int appending : 1;

signed int seekable : 2; /* -1 means unknown */

unsigned int closefd : 1;

unsigned int deallocating: 1;

PyObject *weakreflist;

PyObject *dict;

} fileio;

PyTypeObject PyFileIO_Type;

#define PyFileIO_Check(op) (PyObject_TypeCheck((op), &PyFileIO_Type))

int

_PyFileIO_closed(PyObject *self)

{

return ((fileio *)self)->fd < 0;

}

/* Because this can call arbitrary code, it shouldn't be called when

the refcount is 0 (that is, not directly from tp_dealloc unless

the refcount has been temporarily re-incremented). */

static PyObject *

fileio_dealloc_warn(fileio *self, PyObject *source)

{

if (self->fd >= 0 && self->closefd) {

PyObject *exc, *val, *tb;

PyErr_Fetch(&exc, &val, &tb);

if (PyErr_WarnFormat(PyExc_ResourceWarning, 1,

"unclosed file %R", source)) {

/* Spurious errors can appear at shutdown */

if (PyErr_ExceptionMatches(PyExc_Warning))

PyErr_WriteUnraisable((PyObject *) self);

}

PyErr_Restore(exc, val, tb);

}

Py_RETURN_NONE;

}

static PyObject *

portable_lseek(int fd, PyObject *posobj, int whence);

static PyObject *portable_lseek(int fd, PyObject *posobj, int whence);

/* Returns 0 on success, -1 with exception set on failure. */

static int

internal_close(fileio *self)

{

int err = 0;

int save_errno = 0;

if (self->fd >= 0) {

int fd = self->fd;

self->fd = -1;

/* fd is accessible and someone else may have closed it */

if (_PyVerify_fd(fd)) {

Py_BEGIN_ALLOW_THREADS

err = close(fd);

if (err < 0)

save_errno = errno;

Py_END_ALLOW_THREADS

} else {

save_errno = errno;

err = -1;

}

if (err < 0) {

errno = save_errno;

PyErr_SetFromErrno(PyExc_IOError);

return -1;

}

return 0;

}

static PyObject *

fileio_close(fileio *self)

{

_Py_IDENTIFIER(close);

if (!self->closefd) {

self->fd = -1;

Py_RETURN_NONE;

}

if (self->deallocating) {

PyObject *r = fileio_dealloc_warn(self, (PyObject *) self);

if (r)

Py_DECREF(r);

else

PyErr_Clear();

}

errno = internal_close(self);

if (errno < 0)

return NULL;

return _PyObject_CallMethodId((PyObject*)&PyRawIOBase_Type,

&PyId_close, "O", self);

}

static PyObject *

fileio_new(PyTypeObject *type, PyObject *args, PyObject *kwds)

{

fileio *self;

assert(type != NULL && type->tp_alloc != NULL);

self = (fileio *) type->tp_alloc(type, 0);

if (self != NULL) {

self->fd = -1;

self->created = 0;

self->readable = 0;

self->writable = 0;

self->appending = 0;

self->seekable = -1;

self->closefd = 1;

self->weakreflist = NULL;

}

return (PyObject *) self;

}

/* On Unix, open will succeed for directories.

In Python, there should be no file objects referring to

directories, so we need a check. */

static int

dircheck(fileio* self, PyObject *nameobj)

{

#if defined(HAVE_FSTAT) && defined(S_ISDIR) && defined(EISDIR)

struct stat buf;

if (self->fd < 0)

return 0;

if (fstat(self->fd, &buf) == 0 && S_ISDIR(buf.st_mode)) {

errno = EISDIR;

PyErr_SetFromErrnoWithFilenameObject(PyExc_IOError, nameobj);

return -1;

}

#endif

return 0;

}

static int

check_fd(int fd)

{

#if defined(HAVE_FSTAT)

struct stat buf;

if (!_PyVerify_fd(fd) || (fstat(fd, &buf) < 0 && errno == EBADF)) {

PyObject *exc;

char *msg = strerror(EBADF);

exc = PyObject_CallFunction(PyExc_OSError, "(is)",

EBADF, msg);

PyErr_SetObject(PyExc_OSError, exc);

Py_XDECREF(exc);

return -1;

}

#endif

return 0;

}

static int

fileio_init(PyObject *oself, PyObject *args, PyObject *kwds)

{

fileio *self = (fileio *) oself;

static char *kwlist[] = {"file", "mode", "closefd", "opener", NULL};

const char *name = NULL;

PyObject *nameobj, *stringobj = NULL, *opener = Py_None;

char *mode = "r";

char *s;

#ifdef MS_WINDOWS

Py_UNICODE *widename = NULL;

#endif

int ret = 0;

int rwa = 0, plus = 0;

int flags = 0;

int fd = -1;

int closefd = 1;

int fd_is_own = 0;

assert(PyFileIO_Check(oself));

if (self->fd >= 0) {

if (self->closefd) {

/* Have to close the existing file first. */

if (internal_close(self) < 0)

return -1;

}

else

self->fd = -1;

}

if (!PyArg_ParseTupleAndKeywords(args, kwds, "O|siO:fileio",

kwlist, &nameobj, &mode, &closefd,

&opener))

return -1;

if (PyFloat_Check(nameobj)) {

PyErr_SetString(PyExc_TypeError,

"integer argument expected, got float");

return -1;

}

fd = _PyLong_AsInt(nameobj);

if (fd < 0) {

if (!PyErr_Occurred()) {

PyErr_SetString(PyExc_ValueError,

"Negative filedescriptor");

return -1;

}

PyErr_Clear();

}

#ifdef MS_WINDOWS

if (PyUnicode_Check(nameobj)) {

int rv = _PyUnicode_HasNULChars(nameobj);

if (rv) {

if (rv != -1)

PyErr_SetString(PyExc_TypeError, "embedded NUL character");

return -1;

}

widename = PyUnicode_AsUnicode(nameobj);

if (widename == NULL)

return -1;

} else

#endif

if (fd < 0)

{

if (!PyUnicode_FSConverter(nameobj, &stringobj)) {

return -1;

}

name = PyBytes_AS_STRING(stringobj);

}

s = mode;

while (*s) {

switch (*s++) {

case 'x':

if (rwa) {

bad_mode:

PyErr_SetString(PyExc_ValueError,

"Must have exactly one of create/read/write/append "

"mode and at most one plus");

goto error;

}

rwa = 1;

self->created = 1;

self->writable = 1;

flags |= O_EXCL | O_CREAT;

break;

case 'r':

if (rwa)

goto bad_mode;

rwa = 1;

self->readable = 1;

break;

case 'w':

if (rwa)

goto bad_mode;

rwa = 1;

self->writable = 1;

flags |= O_CREAT | O_TRUNC;

break;

case 'a':

if (rwa)

goto bad_mode;

rwa = 1;

self->writable = 1;

self->appending = 1;

flags |= O_APPEND | O_CREAT;

break;

case 'b':

break;

case '+':

if (plus)

goto bad_mode;

self->readable = self->writable = 1;

plus = 1;

break;

default:

PyErr_Format(PyExc_ValueError,

"invalid mode: %.200s", mode);

goto error;

}

if (!rwa)

goto bad_mode;

if (self->readable && self->writable)

flags |= O_RDWR;

else if (self->readable)

flags |= O_RDONLY;

else

flags |= O_WRONLY;

#ifdef O_BINARY

flags |= O_BINARY;

#endif

if (fd >= 0) {

if (check_fd(fd))

goto error;

self->fd = fd;

self->closefd = closefd;

}

else {

self->closefd = 1;

if (!closefd) {

PyErr_SetString(PyExc_ValueError,

"Cannot use closefd=False with file name");

goto error;

}

errno = 0;

if (opener == Py_None) {

Py_BEGIN_ALLOW_THREADS

#ifdef MS_WINDOWS

if (widename != NULL)

self->fd = _wopen(widename, flags, 0666);

else

#endif

self->fd = open(name, flags, 0666);

Py_END_ALLOW_THREADS

} else {

PyObject *fdobj = PyObject_CallFunction(

opener, "Oi", nameobj, flags);

if (fdobj == NULL)

goto error;

if (!PyLong_Check(fdobj)) {

Py_DECREF(fdobj);

PyErr_SetString(PyExc_TypeError,

"expected integer from opener");

goto error;

}

self->fd = _PyLong_AsInt(fdobj);

Py_DECREF(fdobj);

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

goto error;

}

fd_is_own = 1;

if (self->fd < 0) {

#ifdef MS_WINDOWS

if (widename != NULL)

PyErr_SetFromErrnoWithFilenameObject(PyExc_IOError, nameobj);

else

#endif

PyErr_SetFromErrnoWithFilename(PyExc_IOError, name);

goto error;

}

if (dircheck(self, nameobj) < 0)

goto error;

#if defined(MS_WINDOWS) || defined(__CYGWIN__)

/* don't translate newlines (\r\n <=> \n) */

_setmode(self->fd, O_BINARY);

#endif

if (PyObject_SetAttrString((PyObject *)self, "name", nameobj) < 0)

goto error;

if (self->appending) {

/* For consistent behaviour, we explicitly seek to the

end of file (otherwise, it might be done only on the

first write()). */

PyObject *pos = portable_lseek(self->fd, NULL, 2);

if (pos == NULL)

goto error;

Py_DECREF(pos);

}

goto done;

error:

ret = -1;

if (!fd_is_own)

self->fd = -1;

if (self->fd >= 0)

internal_close(self);

done:

Py_CLEAR(stringobj);

return ret;

}

static int

fileio_traverse(fileio *self, visitproc visit, void *arg)

{

Py_VISIT(self->dict);

return 0;

}

static int

fileio_clear(fileio *self)

{

Py_CLEAR(self->dict);

return 0;

}

static void

fileio_dealloc(fileio *self)

{

self->deallocating = 1;

if (_PyIOBase_finalize((PyObject *) self) < 0)

return;

_PyObject_GC_UNTRACK(self);

if (self->weakreflist != NULL)

PyObject_ClearWeakRefs((PyObject *) self);

Py_CLEAR(self->dict);

Py_TYPE(self)->tp_free((PyObject *)self);

}

static PyObject *

err_closed(void)

{

PyErr_SetString(PyExc_ValueError, "I/O operation on closed file");

return NULL;

}

static PyObject *

err_mode(char *action)

{

PyErr_Format(IO_STATE->unsupported_operation,

"File not open for %s", action);

return NULL;

}

static PyObject *

fileio_fileno(fileio *self)

{

if (self->fd < 0)

return err_closed();

return PyLong_FromLong((long) self->fd);

}

static PyObject *

fileio_readable(fileio *self)

{

if (self->fd < 0)

return err_closed();

return PyBool_FromLong((long) self->readable);

}

static PyObject *

fileio_writable(fileio *self)

{

if (self->fd < 0)

return err_closed();

return PyBool_FromLong((long) self->writable);

}

static PyObject *

fileio_seekable(fileio *self)

{

if (self->fd < 0)

return err_closed();

if (self->seekable < 0) {

PyObject *pos = portable_lseek(self->fd, NULL, SEEK_CUR);

if (pos == NULL) {

PyErr_Clear();

self->seekable = 0;

} else {

Py_DECREF(pos);

self->seekable = 1;

}

return PyBool_FromLong((long) self->seekable);

}

static PyObject *

fileio_readinto(fileio *self, PyObject *args)

{

Py_buffer pbuf;

Py_ssize_t n, len;

int err;

if (self->fd < 0)

return err_closed();

if (!self->readable)

return err_mode("reading");

if (!PyArg_ParseTuple(args, "w*", &pbuf))

return NULL;

if (_PyVerify_fd(self->fd)) {

len = pbuf.len;

Py_BEGIN_ALLOW_THREADS

errno = 0;

#if defined(MS_WIN64) || defined(MS_WINDOWS)

if (len > INT_MAX)

len = INT_MAX;

n = read(self->fd, pbuf.buf, (int)len);

#else

n = read(self->fd, pbuf.buf, len);

#endif

Py_END_ALLOW_THREADS

} else

n = -1;

err = errno;

PyBuffer_Release(&pbuf);

if (n < 0) {

if (err == EAGAIN)

Py_RETURN_NONE;

errno = err;

PyErr_SetFromErrno(PyExc_IOError);

return NULL;

}

return PyLong_FromSsize_t(n);

}

static size_t

new_buffersize(fileio *self, size_t currentsize

#ifdef HAVE_FSTAT

, Py_off_t pos, Py_off_t end

#endif

)

{

size_t addend;

#ifdef HAVE_FSTAT

if (end != (Py_off_t)-1) {

/* Files claiming a size smaller than SMALLCHUNK may

actually be streaming pseudo-files. In this case, we

apply the more aggressive algorithm below.

if (end >= SMALLCHUNK && end >= pos && pos >= 0) {

/* Add 1 so if the file were to grow we'd notice. */

Py_off_t bufsize = currentsize + end - pos + 1;

if (bufsize < PY_SSIZE_T_MAX)

return (size_t)bufsize;

else

return PY_SSIZE_T_MAX;

}

#endif

/* Expand the buffer by an amount proportional to the current size,

giving us amortized linear-time behavior. For bigger sizes, use a

less-than-double growth factor to avoid excessive allocation. */

if (currentsize > 65536)

addend = currentsize >> 3;

else

addend = 256 + currentsize;

if (addend < SMALLCHUNK)

/* Avoid tiny read() calls. */

addend = SMALLCHUNK;

return addend + currentsize;

}

static PyObject *

fileio_readall(fileio *self)

{

#ifdef HAVE_FSTAT

struct stat st;

Py_off_t pos, end;

#endif

PyObject *result;

Py_ssize_t total = 0;

Py_ssize_t n;

size_t newsize;

if (self->fd < 0)

return err_closed();

if (!_PyVerify_fd(self->fd))

return PyErr_SetFromErrno(PyExc_IOError);

result = PyBytes_FromStringAndSize(NULL, SMALLCHUNK);

if (result == NULL)

return NULL;

#ifdef HAVE_FSTAT

#if defined(MS_WIN64) || defined(MS_WINDOWS)

pos = _lseeki64(self->fd, 0L, SEEK_CUR);

#else

pos = lseek(self->fd, 0L, SEEK_CUR);

#endif

if (fstat(self->fd, &st) == 0)

end = st.st_size;

else

end = (Py_off_t)-1;

#endif

while (1) {

#ifdef HAVE_FSTAT

newsize = new_buffersize(self, total, pos, end);

#else

newsize = new_buffersize(self, total);

#endif

if (newsize > PY_SSIZE_T_MAX || newsize <= 0) {

PyErr_SetString(PyExc_OverflowError,

"unbounded read returned more bytes "

"than a Python string can hold ");

Py_DECREF(result);

return NULL;

}

if (PyBytes_GET_SIZE(result) < (Py_ssize_t)newsize) {

if (_PyBytes_Resize(&result, newsize) < 0) {

if (total == 0) {

Py_DECREF(result);

return NULL;

}

PyErr_Clear();

break;

}

Py_BEGIN_ALLOW_THREADS

errno = 0;

n = newsize - total;

#if defined(MS_WIN64) || defined(MS_WINDOWS)

if (n > INT_MAX)

n = INT_MAX;

n = read(self->fd,

PyBytes_AS_STRING(result) + total,

(int)n);

#else

n = read(self->fd,

PyBytes_AS_STRING(result) + total,

n);

#endif

Py_END_ALLOW_THREADS

if (n == 0)

break;

if (n < 0) {

if (errno == EINTR) {

if (PyErr_CheckSignals()) {

Py_DECREF(result);

return NULL;

}

continue;

}

if (total > 0)

break;

if (errno == EAGAIN) {

Py_DECREF(result);

Py_RETURN_NONE;

}

Py_DECREF(result);

PyErr_SetFromErrno(PyExc_IOError);

return NULL;

}

total += n;

#ifdef HAVE_FSTAT

pos += n;

#endif

}

if (PyBytes_GET_SIZE(result) > total) {

if (_PyBytes_Resize(&result, total) < 0) {

/* This should never happen, but just in case */

Py_DECREF(result);

return NULL;

}

return result;

}

static PyObject *

fileio_read(fileio *self, PyObject *args)

{

char *ptr;

Py_ssize_t n;

Py_ssize_t size = -1;

PyObject *bytes;

if (self->fd < 0)

return err_closed();

if (!self->readable)

return err_mode("reading");

if (!PyArg_ParseTuple(args, "|O&", &_PyIO_ConvertSsize_t, &size))

return NULL;

if (size < 0) {

return fileio_readall(self);

}

#if defined(MS_WIN64) || defined(MS_WINDOWS)

if (size > INT_MAX)

size = INT_MAX;

#endif

bytes = PyBytes_FromStringAndSize(NULL, size);

if (bytes == NULL)

return NULL;

ptr = PyBytes_AS_STRING(bytes);

if (_PyVerify_fd(self->fd)) {

Py_BEGIN_ALLOW_THREADS

errno = 0;

#if defined(MS_WIN64) || defined(MS_WINDOWS)

n = read(self->fd, ptr, (int)size);

#else

n = read(self->fd, ptr, size);

#endif

Py_END_ALLOW_THREADS

} else

n = -1;

if (n < 0) {

int err = errno;

Py_DECREF(bytes);

if (err == EAGAIN)

Py_RETURN_NONE;

errno = err;

PyErr_SetFromErrno(PyExc_IOError);

return NULL;

}

if (n != size) {

if (_PyBytes_Resize(&bytes, n) < 0) {

Py_DECREF(bytes);

return NULL;

}

return (PyObject *) bytes;

}

static PyObject *

fileio_write(fileio *self, PyObject *args)

{

Py_buffer pbuf;

Py_ssize_t n, len;

int err;

if (self->fd < 0)

return err_closed();

if (!self->writable)

return err_mode("writing");

if (!PyArg_ParseTuple(args, "y*", &pbuf))

return NULL;

if (_PyVerify_fd(self->fd)) {

Py_BEGIN_ALLOW_THREADS

errno = 0;

len = pbuf.len;

#if defined(MS_WIN64) || defined(MS_WINDOWS)

if (len > 32767 && isatty(self->fd)) {

/* Issue #11395: the Windows console returns an error (12: not

enough space error) on writing into stdout if stdout mode is

binary and the length is greater than 66,000 bytes (or less,

depending on heap usage). */

len = 32767;

}

else if (len > INT_MAX)

len = INT_MAX;

n = write(self->fd, pbuf.buf, (int)len);

#else

n = write(self->fd, pbuf.buf, len);

#endif

Py_END_ALLOW_THREADS

} else

n = -1;

err = errno;

PyBuffer_Release(&pbuf);

if (n < 0) {

if (err == EAGAIN)

Py_RETURN_NONE;

errno = err;

PyErr_SetFromErrno(PyExc_IOError);

return NULL;

}

return PyLong_FromSsize_t(n);

}

/* XXX Windows support below is likely incomplete */

/* Cribbed from posix_lseek() */

static PyObject *

portable_lseek(int fd, PyObject *posobj, int whence)

{

Py_off_t pos, res;

#ifdef SEEK_SET

/* Turn 0, 1, 2 into SEEK_{SET,CUR,END} */

switch (whence) {

#if SEEK_SET != 0

case 0: whence = SEEK_SET; break;

#endif

#if SEEK_CUR != 1

case 1: whence = SEEK_CUR; break;

#endif

#if SEEK_END != 2

case 2: whence = SEEK_END; break;

#endif

}

#endif /* SEEK_SET */

if (posobj == NULL)

pos = 0;

else {

if(PyFloat_Check(posobj)) {

PyErr_SetString(PyExc_TypeError, "an integer is required");

return NULL;

}

#if defined(HAVE_LARGEFILE_SUPPORT)

pos = PyLong_AsLongLong(posobj);

#else

pos = PyLong_AsLong(posobj);

#endif

if (PyErr_Occurred())

return NULL;

}

if (_PyVerify_fd(fd)) {

Py_BEGIN_ALLOW_THREADS

#if defined(MS_WIN64) || defined(MS_WINDOWS)

res = _lseeki64(fd, pos, whence);

#else

res = lseek(fd, pos, whence);

#endif

Py_END_ALLOW_THREADS

} else

res = -1;

if (res < 0)

return PyErr_SetFromErrno(PyExc_IOError);

#if defined(HAVE_LARGEFILE_SUPPORT)

return PyLong_FromLongLong(res);

#else

return PyLong_FromLong(res);

#endif

}

static PyObject *

fileio_seek(fileio *self, PyObject *args)

{

PyObject *posobj;

int whence = 0;

if (self->fd < 0)

return err_closed();

if (!PyArg_ParseTuple(args, "O|i", &posobj, &whence))

return NULL;

return portable_lseek(self->fd, posobj, whence);

}

static PyObject *

fileio_tell(fileio *self, PyObject *args)

{

if (self->fd < 0)

return err_closed();

return portable_lseek(self->fd, NULL, 1);

}

#ifdef HAVE_FTRUNCATE

static PyObject *

fileio_truncate(fileio *self, PyObject *args)

{

PyObject *posobj = NULL; /* the new size wanted by the user */

#ifndef MS_WINDOWS

Py_off_t pos;

#endif

int ret;

int fd;

fd = self->fd;

if (fd < 0)

return err_closed();

if (!self->writable)

return err_mode("writing");

if (!PyArg_ParseTuple(args, "|O", &posobj))

return NULL;

if (posobj == Py_None || posobj == NULL) {

/* Get the current position. */

posobj = portable_lseek(fd, NULL, 1);

if (posobj == NULL)

return NULL;

}

else {

Py_INCREF(posobj);

}

#ifdef MS_WINDOWS

/* MS _chsize doesn't work if newsize doesn't fit in 32 bits,

so don't even try using it. */

{

PyObject *oldposobj, *tempposobj;

HANDLE hFile;

/* we save the file pointer position */

oldposobj = portable_lseek(fd, NULL, 1);

if (oldposobj == NULL) {

Py_DECREF(posobj);

return NULL;

}

/* we then move to the truncation position */

tempposobj = portable_lseek(fd, posobj, 0);

if (tempposobj == NULL) {

Py_DECREF(oldposobj);

Py_DECREF(posobj);

return NULL;

}

Py_DECREF(tempposobj);

/* Truncate. Note that this may grow the file! */

Py_BEGIN_ALLOW_THREADS

errno = 0;

hFile = (HANDLE)_get_osfhandle(fd);

ret = hFile == (HANDLE)-1; /* testing for INVALID_HANDLE value */

if (ret == 0) {

ret = SetEndOfFile(hFile) == 0;

if (ret)

errno = EACCES;

}

Py_END_ALLOW_THREADS

/* we restore the file pointer position in any case */

tempposobj = portable_lseek(fd, oldposobj, 0);

Py_DECREF(oldposobj);

if (tempposobj == NULL) {

Py_DECREF(posobj);

return NULL;

}

Py_DECREF(tempposobj);

}

#else

#if defined(HAVE_LARGEFILE_SUPPORT)

pos = PyLong_AsLongLong(posobj);

#else

pos = PyLong_AsLong(posobj);

#endif

if (PyErr_Occurred()){

Py_DECREF(posobj);

return NULL;

}

Py_BEGIN_ALLOW_THREADS

errno = 0;

ret = ftruncate(fd, pos);

Py_END_ALLOW_THREADS

#endif /* !MS_WINDOWS */

if (ret != 0) {

Py_DECREF(posobj);

PyErr_SetFromErrno(PyExc_IOError);

return NULL;

}

return posobj;

}

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cpython/Modules/_io/fileio.c at 3.3 · python/cpython · GitHub

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