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'") 55