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26492c0a14
This change continues the improvements to compile-time out of bounds checking by decorating more APIs with either attribute access, or by explicitly providing the array bound in APIs such as tmpnam() that expect arrays of some minimum size as arguments. (The latter feature is new in GCC 11.) The only effects of the attribute and/or the array bound is to check and diagnose calls to the functions that fail to provide a sufficient number of elements, and the definitions of the functions that access elements outside the specified bounds. (There is no interplay with _FORTIFY_SOURCE here yet.) Tested with GCC 7 through 11 on x86_64-linux.
52 lines
1.7 KiB
C
52 lines
1.7 KiB
C
/* Copyright (C) 1991-2021 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 <stdio.h>
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#include <string.h>
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static char tmpnam_buffer[L_tmpnam];
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/* Generate a unique filename in P_tmpdir.
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This function is *not* thread safe! */
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char *
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tmpnam (char s[L_tmpnam])
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{
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/* By using two buffers we manage to be thread safe in the case
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where S != NULL. */
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char tmpbufmem[L_tmpnam];
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char *tmpbuf = s ?: tmpbufmem;
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/* In the following call we use the buffer pointed to by S if
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non-NULL although we don't know the size. But we limit the size
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to L_tmpnam characters in any case. */
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if (__builtin_expect (__path_search (tmpbuf, L_tmpnam, NULL, NULL, 0),
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0))
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return NULL;
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if (__glibc_unlikely (__gen_tempname (tmpbuf, 0, 0, __GT_NOCREATE)))
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return NULL;
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if (s == NULL)
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return (char *) memcpy (tmpnam_buffer, tmpbuf, L_tmpnam);
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return s;
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}
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link_warning (tmpnam,
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"the use of `tmpnam' is dangerous, better use `mkstemp'")
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