src/system/libroot/posix/glibc/stdio-common/tmpnam.c

   1 /* Copyright (C) 1991,1993,1996-1999,2000 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3
   4    The GNU C Library is free software; you can redistribute it and/or
   5    modify it under the terms of the GNU Lesser General Public
   6    License as published by the Free Software Foundation; either
   7    version 2.1 of the License, or (at your option) any later version.
   8
   9    The GNU C Library is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12    Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public
  15    License along with the GNU C Library; if not, write to the Free
  16    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  17    02111-1307 USA.
  18 */
  19
  20
  21 #include <stdio_private.h>
  22 #include <string.h>
  23
  24
  25 /** Generate a unique filename in P_tmpdir.
  26  *      This function is *not* thread safe!
  27  */
  28
  29 char *
  30 tmpnam (char *s)
  31 {
  32         static char tmpnam_buffer[L_tmpnam];
  33
  34         /* By using two buffers we manage to be thread safe in the case where S != NULL.  */
  35         char tmpbufmem[L_tmpnam];
  36         char *tmpbuf = s ?: tmpbufmem;
  37
  38         /* In the following call we use the buffer pointed to by S if
  39          * non-NULL although we don't know the size.  But we limit the size
  40          * to L_tmpnam characters in any case.
  41          */
  42         if (__builtin_expect(__path_search(tmpbuf, L_tmpnam, NULL, NULL, 0), 0))
  43                 return NULL;
  44
  45         if (__builtin_expect(__gen_tempname(tmpbuf, __GT_NOCREATE), 0))
  46                 return NULL;
  47
  48         if (s == NULL)
  49                 return (char *)memcpy(tmpnam_buffer, tmpbuf, L_tmpnam);
  50
  51         return s;
  52 }
  53
  54 //link_warning (tmpnam, "the use of `tmpnam' is dangerous, better use `mkstemp'")