52dd322420
* vsnprintf.c (vsnprintf): Don't pad string with extra nulls. (main): Test that we don't write too much data. From-SVN: r65955
154 lines
4.2 KiB
C
154 lines
4.2 KiB
C
/* Implement the vsnprintf function.
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Copyright (C) 2003 Free Software Foundation, Inc.
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Written by Kaveh R. Ghazi <ghazi@caip.rutgers.edu>.
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This file is part of the libiberty library. This library is free
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software; you can redistribute it and/or modify it under the
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terms of the GNU General Public License as published by the
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Free Software Foundation; either version 2, or (at your option)
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any later version.
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This 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
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GNU 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 GNU CC; see the file COPYING. If not, write to
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the Free Software Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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As a special exception, if you link this library with files
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compiled with a GNU compiler to produce an executable, this does not cause
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the resulting executable to be covered by the GNU General Public License.
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This exception does not however invalidate any other reasons why
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the executable file might be covered by the GNU General Public License. */
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/*
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@deftypefn Supplemental int vsnprintf (char *@var{buf}, size_t @var{n}, const char *@var{format}, va_list @var{ap})
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This function is similar to vsprintf, but it will print at most
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@var{n} characters. On error the return value is -1, otherwise it
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returns the number of characters that would have been printed had
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@var{n} been sufficiently large, regardless of the actual value of
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@var{n}. Note some pre-C99 system libraries do not implement this
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correctly so users cannot generally rely on the return value if the
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system version of this function is used.
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@end deftypefn
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*/
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#include "config.h"
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#include "ansidecl.h"
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#ifdef ANSI_PROTOTYPES
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#include <stdarg.h>
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#else
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#include <varargs.h>
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#endif
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#ifdef HAVE_STRING_H
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#include <string.h>
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#endif
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#ifdef HAVE_STDLIB_H
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#include <stdlib.h>
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#endif
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#include "libiberty.h"
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/* This implementation relies on a working vasprintf. */
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int
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vsnprintf (s, n, format, ap)
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char * s;
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size_t n;
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const char *format;
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va_list ap;
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{
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char *buf = 0;
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int result = vasprintf (&buf, format, ap);
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if (!buf)
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return -1;
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if (result < 0)
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{
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free (buf);
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return -1;
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}
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result = strlen (buf);
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if (n > 0)
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{
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if ((long) n > result)
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memcpy (s, buf, result+1);
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else
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{
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memcpy (s, buf, n-1);
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s[n - 1] = 0;
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}
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}
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free (buf);
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return result;
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}
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#ifdef TEST
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/* Set the buffer to a known state. */
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#define CLEAR(BUF) do { memset ((BUF), 'X', sizeof (BUF)); (BUF)[14] = '\0'; } while (0)
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/* For assertions. */
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#define VERIFY(P) do { if (!(P)) abort(); } while (0)
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static int ATTRIBUTE_PRINTF_3
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checkit VPARAMS ((char *s, size_t n, const char *format, ...))
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{
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int result;
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VA_OPEN (ap, format);
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VA_FIXEDARG (ap, char *, s);
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VA_FIXEDARG (ap, size_t, n);
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VA_FIXEDARG (ap, const char *, format);
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result = vsnprintf (s, n, format, ap);
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VA_CLOSE (ap);
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return result;
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}
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extern int main PARAMS ((void));
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int
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main ()
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{
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char buf[128];
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int status;
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CLEAR (buf);
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status = checkit (buf, 10, "%s:%d", "foobar", 9);
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VERIFY (status==8 && memcmp (buf, "foobar:9\0XXXXX\0", 15) == 0);
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CLEAR (buf);
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status = checkit (buf, 9, "%s:%d", "foobar", 9);
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VERIFY (status==8 && memcmp (buf, "foobar:9\0XXXXX\0", 15) == 0);
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CLEAR (buf);
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status = checkit (buf, 8, "%s:%d", "foobar", 9);
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VERIFY (status==8 && memcmp (buf, "foobar:\0XXXXXX\0", 15) == 0);
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CLEAR (buf);
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status = checkit (buf, 7, "%s:%d", "foobar", 9);
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VERIFY (status==8 && memcmp (buf, "foobar\0XXXXXXX\0", 15) == 0);
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CLEAR (buf);
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status = checkit (buf, 6, "%s:%d", "foobar", 9);
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VERIFY (status==8 && memcmp (buf, "fooba\0XXXXXXXX\0", 15) == 0);
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CLEAR (buf);
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status = checkit (buf, 2, "%s:%d", "foobar", 9);
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VERIFY (status==8 && memcmp (buf, "f\0XXXXXXXXXXXX\0", 15) == 0);
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CLEAR (buf);
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status = checkit (buf, 1, "%s:%d", "foobar", 9);
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VERIFY (status==8 && memcmp (buf, "\0XXXXXXXXXXXXX\0", 15) == 0);
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CLEAR (buf);
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status = checkit (buf, 0, "%s:%d", "foobar", 9);
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VERIFY (status==8 && memcmp (buf, "XXXXXXXXXXXXXX\0", 15) == 0);
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return 0;
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}
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#endif /* TEST */
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