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1"""Test largefile support on system where this makes sense.
2"""
3
4import os
5import stat
6import sys
7import unittest
8import socket
9import shutil
10import threading
11from test.support import requires, bigmemtest
12from test.support import SHORT_TIMEOUT
13from test.support import socket_helper
14from test.support.os_helper import TESTFN, unlink
15import io  # C implementation of io
16import _pyio as pyio # Python implementation of io
17
18# size of file to create (>2 GiB; 2 GiB == 2,147,483,648 bytes)
19size = 2_500_000_000
20TESTFN2 = TESTFN + '2'
21
22
23class LargeFileTest:
24
25    def setUp(self):
26        if os.path.exists(TESTFN):
27            mode = 'r+b'
28        else:
29            mode = 'w+b'
30
31        with self.open(TESTFN, mode) as f:
32            current_size = os.fstat(f.fileno())[stat.ST_SIZE]
33            if current_size == size+1:
34                return
35
36            if current_size == 0:
37                f.write(b'z')
38
39            f.seek(0)
40            f.seek(size)
41            f.write(b'a')
42            f.flush()
43            self.assertEqual(os.fstat(f.fileno())[stat.ST_SIZE], size+1)
44
45    @classmethod
46    def tearDownClass(cls):
47        with cls.open(TESTFN, 'wb'):
48            pass
49        if not os.stat(TESTFN)[stat.ST_SIZE] == 0:
50            raise cls.failureException('File was not truncated by opening '
51                                       'with mode "wb"')
52        unlink(TESTFN2)
53
54
55class TestFileMethods(LargeFileTest):
56    """Test that each file function works as expected for large
57    (i.e. > 2 GiB) files.
58    """
59
60    # _pyio.FileIO.readall() uses a temporary bytearray then casted to bytes,
61    # so memuse=2 is needed
62    @bigmemtest(size=size, memuse=2, dry_run=False)
63    def test_large_read(self, _size):
64        # bpo-24658: Test that a read greater than 2GB does not fail.
65        with self.open(TESTFN, "rb") as f:
66            self.assertEqual(len(f.read()), size + 1)
67            self.assertEqual(f.tell(), size + 1)
68
69    def test_osstat(self):
70        self.assertEqual(os.stat(TESTFN)[stat.ST_SIZE], size+1)
71
72    def test_seek_read(self):
73        with self.open(TESTFN, 'rb') as f:
74            self.assertEqual(f.tell(), 0)
75            self.assertEqual(f.read(1), b'z')
76            self.assertEqual(f.tell(), 1)
77            f.seek(0)
78            self.assertEqual(f.tell(), 0)
79            f.seek(0, 0)
80            self.assertEqual(f.tell(), 0)
81            f.seek(42)
82            self.assertEqual(f.tell(), 42)
83            f.seek(42, 0)
84            self.assertEqual(f.tell(), 42)
85            f.seek(42, 1)
86            self.assertEqual(f.tell(), 84)
87            f.seek(0, 1)
88            self.assertEqual(f.tell(), 84)
89            f.seek(0, 2)  # seek from the end
90            self.assertEqual(f.tell(), size + 1 + 0)
91            f.seek(-10, 2)
92            self.assertEqual(f.tell(), size + 1 - 10)
93            f.seek(-size-1, 2)
94            self.assertEqual(f.tell(), 0)
95            f.seek(size)
96            self.assertEqual(f.tell(), size)
97            # the 'a' that was written at the end of file above
98            self.assertEqual(f.read(1), b'a')
99            f.seek(-size-1, 1)
100            self.assertEqual(f.read(1), b'z')
101            self.assertEqual(f.tell(), 1)
102
103    def test_lseek(self):
104        with self.open(TESTFN, 'rb') as f:
105            self.assertEqual(os.lseek(f.fileno(), 0, 0), 0)
106            self.assertEqual(os.lseek(f.fileno(), 42, 0), 42)
107            self.assertEqual(os.lseek(f.fileno(), 42, 1), 84)
108            self.assertEqual(os.lseek(f.fileno(), 0, 1), 84)
109            self.assertEqual(os.lseek(f.fileno(), 0, 2), size+1+0)
110            self.assertEqual(os.lseek(f.fileno(), -10, 2), size+1-10)
111            self.assertEqual(os.lseek(f.fileno(), -size-1, 2), 0)
112            self.assertEqual(os.lseek(f.fileno(), size, 0), size)
113            # the 'a' that was written at the end of file above
114            self.assertEqual(f.read(1), b'a')
115
116    def test_truncate(self):
117        with self.open(TESTFN, 'r+b') as f:
118            if not hasattr(f, 'truncate'):
119                raise unittest.SkipTest("open().truncate() not available "
120                                        "on this system")
121            f.seek(0, 2)
122            # else we've lost track of the true size
123            self.assertEqual(f.tell(), size+1)
124            # Cut it back via seek + truncate with no argument.
125            newsize = size - 10
126            f.seek(newsize)
127            f.truncate()
128            self.assertEqual(f.tell(), newsize)  # else pointer moved
129            f.seek(0, 2)
130            self.assertEqual(f.tell(), newsize)  # else wasn't truncated
131            # Ensure that truncate(smaller than true size) shrinks
132            # the file.
133            newsize -= 1
134            f.seek(42)
135            f.truncate(newsize)
136            self.assertEqual(f.tell(), 42)
137            f.seek(0, 2)
138            self.assertEqual(f.tell(), newsize)
139            # XXX truncate(larger than true size) is ill-defined
140            # across platform; cut it waaaaay back
141            f.seek(0)
142            f.truncate(1)
143            self.assertEqual(f.tell(), 0)       # else pointer moved
144            f.seek(0)
145            self.assertEqual(len(f.read()), 1)  # else wasn't truncated
146
147    def test_seekable(self):
148        # Issue #5016; seekable() can return False when the current position
149        # is negative when truncated to an int.
150        for pos in (2**31-1, 2**31, 2**31+1):
151            with self.open(TESTFN, 'rb') as f:
152                f.seek(pos)
153                self.assertTrue(f.seekable())
154
155
156def skip_no_disk_space(path, required):
157    def decorator(fun):
158        def wrapper(*args, **kwargs):
159            if shutil.disk_usage(os.path.realpath(path)).free < required:
160                hsize = int(required / 1024 / 1024)
161                raise unittest.SkipTest(
162                    f"required {hsize} MiB of free disk space")
163            return fun(*args, **kwargs)
164        return wrapper
165    return decorator
166
167
168class TestCopyfile(LargeFileTest, unittest.TestCase):
169    open = staticmethod(io.open)
170
171    # Exact required disk space would be (size * 2), but let's give it a
172    # bit more tolerance.
173    @skip_no_disk_space(TESTFN, size * 2.5)
174    def test_it(self):
175        # Internally shutil.copyfile() can use "fast copy" methods like
176        # os.sendfile().
177        size = os.path.getsize(TESTFN)
178        shutil.copyfile(TESTFN, TESTFN2)
179        self.assertEqual(os.path.getsize(TESTFN2), size)
180        with open(TESTFN2, 'rb') as f:
181            self.assertEqual(f.read(5), b'z\x00\x00\x00\x00')
182            f.seek(size - 5)
183            self.assertEqual(f.read(), b'\x00\x00\x00\x00a')
184
185
186@unittest.skipIf(not hasattr(os, 'sendfile'), 'sendfile not supported')
187class TestSocketSendfile(LargeFileTest, unittest.TestCase):
188    open = staticmethod(io.open)
189    timeout = SHORT_TIMEOUT
190
191    def setUp(self):
192        super().setUp()
193        self.thread = None
194
195    def tearDown(self):
196        super().tearDown()
197        if self.thread is not None:
198            self.thread.join(self.timeout)
199            self.thread = None
200
201    def tcp_server(self, sock):
202        def run(sock):
203            with sock:
204                conn, _ = sock.accept()
205                conn.settimeout(self.timeout)
206                with conn, open(TESTFN2, 'wb') as f:
207                    event.wait(self.timeout)
208                    while True:
209                        chunk = conn.recv(65536)
210                        if not chunk:
211                            return
212                        f.write(chunk)
213
214        event = threading.Event()
215        sock.settimeout(self.timeout)
216        self.thread = threading.Thread(target=run, args=(sock, ))
217        self.thread.start()
218        event.set()
219
220    # Exact required disk space would be (size * 2), but let's give it a
221    # bit more tolerance.
222    @skip_no_disk_space(TESTFN, size * 2.5)
223    def test_it(self):
224        port = socket_helper.find_unused_port()
225        with socket.create_server(("", port)) as sock:
226            self.tcp_server(sock)
227            with socket.create_connection(("127.0.0.1", port)) as client:
228                with open(TESTFN, 'rb') as f:
229                    client.sendfile(f)
230        self.tearDown()
231
232        size = os.path.getsize(TESTFN)
233        self.assertEqual(os.path.getsize(TESTFN2), size)
234        with open(TESTFN2, 'rb') as f:
235            self.assertEqual(f.read(5), b'z\x00\x00\x00\x00')
236            f.seek(size - 5)
237            self.assertEqual(f.read(), b'\x00\x00\x00\x00a')
238
239
240def setUpModule():
241    try:
242        import signal
243        # The default handler for SIGXFSZ is to abort the process.
244        # By ignoring it, system calls exceeding the file size resource
245        # limit will raise OSError instead of crashing the interpreter.
246        signal.signal(signal.SIGXFSZ, signal.SIG_IGN)
247    except (ImportError, AttributeError):
248        pass
249
250    # On Windows and Mac OSX this test consumes large resources; It
251    # takes a long time to build the >2 GiB file and takes >2 GiB of disk
252    # space therefore the resource must be enabled to run this test.
253    # If not, nothing after this line stanza will be executed.
254    if sys.platform[:3] == 'win' or sys.platform == 'darwin':
255        requires('largefile',
256                 'test requires %s bytes and a long time to run' % str(size))
257    else:
258        # Only run if the current filesystem supports large files.
259        # (Skip this test on Windows, since we now always support
260        # large files.)
261        f = open(TESTFN, 'wb', buffering=0)
262        try:
263            # 2**31 == 2147483648
264            f.seek(2147483649)
265            # Seeking is not enough of a test: you must write and flush, too!
266            f.write(b'x')
267            f.flush()
268        except (OSError, OverflowError):
269            raise unittest.SkipTest("filesystem does not have "
270                                    "largefile support")
271        finally:
272            f.close()
273            unlink(TESTFN)
274
275
276class CLargeFileTest(TestFileMethods, unittest.TestCase):
277    open = staticmethod(io.open)
278
279
280class PyLargeFileTest(TestFileMethods, unittest.TestCase):
281    open = staticmethod(pyio.open)
282
283
284def tearDownModule():
285    unlink(TESTFN)
286    unlink(TESTFN2)
287
288
289if __name__ == '__main__':
290    unittest.main()
291