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77 lines
2.6 KiB
C
77 lines
2.6 KiB
C
/* test-snprintf - Check whether snprintf allows doubly used strings.
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Copyright (C) 2020-2025 Free Software Foundation, Inc.
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This file is part of GNU Inetutils.
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GNU Inetutils is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or (at
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your option) any later version.
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GNU Inetutils is distributed in the hope that it will be useful, but
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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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General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see `http://www.gnu.org/licenses/'. */
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/* Written by Mats Erik Andersson. */
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/*
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* It is not in violation of POSIX, but implementations of snprintf()
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* differ in their ability to handle a situation where the target string
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* to be produced by snprintf() is at the same time providing data, which
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* are to be passed through the format string, and to be part of the new
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* resulting string. The different BSD unices, as well as OpenSolaris,
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* are known to correctly handle this, whereas glibc is known to fail.
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*
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* This test issues a warning that non-portable behaviour is possible,
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* should the program detect a discrepancy on this system. If the
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* program detects the macro PACKAGE to have value "inetutils", then
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* get attention with the exit value 77, to fit with our testing
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* frame work.
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*
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* When the environment variable VERBOSE is defined, an encouraging
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* message is issued also in the presence of an enhanced implementation
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* of snprintf().
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*/
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#include <config.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#define MESSAGE "try a fool"
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#define WRONG_MESSAGE "fool"
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int
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main (void)
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{
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int err = 0;
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char msg[sizeof (MESSAGE)] = "try a ";
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snprintf (msg, sizeof (msg), "%s%s", msg, WRONG_MESSAGE);
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if (!strcmp (msg, WRONG_MESSAGE))
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{
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printf ("Warning! This implementation of snprintf() is not able\n"
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"to handle string variables that appear as target and at the\n"
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"same time as source. This might be a portability issue!\n");
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#ifdef PACKAGE
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if (!strcmp (PACKAGE, "inetutils"))
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err = 77;
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#endif
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}
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else if (getenv ("VERBOSE"))
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{
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printf ("The present implementation of snprintf() allows the same\n"
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"string to act as target as well as source. Good news!\n");
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}
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/* Always return successfully, as we are only producing a reminder,
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rather than a show stopper. */
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return err;
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}
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