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Add new file libio/tst-fclose-unopened2.c that tests whether fclose on an unopened file returns EOF. This test differs from tst-fclose-unopened.c by ensuring the file's buffer is allocated prior to double-fclose. A comment in tst-fclose-unopened.c now clarifies that it is testing a file with an unallocated buffer. Calling fclose on unopened files normally causes a use-after-free bug, however the standard streams are an exception since they are not deallocated by fclose. Tested for x86_64. Reviewed-by: Carlos O'Donell <carlos@redhat.com>
52 lines
1.7 KiB
C
52 lines
1.7 KiB
C
/* Test using fclose on an unopened file.
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Copyright (C) 2024 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<https://www.gnu.org/licenses/>. */
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#include <mcheck.h>
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#include <stdio.h>
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#include <support/check.h>
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/* Verify that fclose on an unopened file returns EOF. This test uses
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a file with an allocated buffer.
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This is not part of the fclose external contract but there are
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dependencies on this behaviour. */
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static int
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do_test (void)
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{
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mtrace ();
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/* Input file tst-fclose-unopened2.input has 6 bytes plus newline. */
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char buf[6];
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/* Read from the file to ensure its internal buffer is allocated. */
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TEST_COMPARE (fread (buf, 1, sizeof (buf), stdin), sizeof (buf));
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TEST_COMPARE (fclose (stdin), 0);
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/* Attempt to close the unopened file and verify that EOF is returned.
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Calling fclose on a file twice normally causes a use-after-free bug,
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however the standard streams are an exception since they are not
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deallocated by fclose. */
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TEST_COMPARE (fclose (stdin), EOF);
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return 0;
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}
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#include <support/test-driver.c>
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