stdio/FreeBSD/tmpfile.c

   1 /*-
   2  * Copyright (c) 1990, 1993
   3  *      The Regents of the University of California.  All rights reserved.
   4  *
   5  * This code is derived from software contributed to Berkeley by
   6  * Chris Torek.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions
  10  * are met:
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice, this list of conditions and the following disclaimer.
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  * 3. Neither the name of the University nor the names of its contributors
  17  *    may be used to endorse or promote products derived from this software
  18  *    without specific prior written permission.
  19  *
  20  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  21  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  22  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  23  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  24  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  25  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  26  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  27  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  28  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  29  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  30  * SUCH DAMAGE.
  31  */
  32
  33 #if defined(LIBC_SCCS) && !defined(lint)
  34 static char sccsid[] = "@(#)tmpfile.c   8.1 (Berkeley) 6/4/93";
  35 #endif /* LIBC_SCCS and not lint */
  36 #include <sys/cdefs.h>
  37 __FBSDID("$FreeBSD: src/lib/libc/stdio/tmpfile.c,v 1.10 2007/01/09 00:28:07 imp Exp $");
  38
  39 #include "namespace.h"
  40 #include <sys/types.h>
  41 #include <signal.h>
  42 #include <unistd.h>
  43 #include <errno.h>
  44 #include <stdio.h>
  45 #include <stdlib.h>
  46 #include <string.h>
  47 #include <paths.h>
  48 #include "un-namespace.h"
  49
  50 FILE *
  51 tmpfile(void)
  52 {
  53         sigset_t set, oset;
  54         FILE *fp;
  55         int fd, sverrno;
  56 #define TRAILER "tmp.XXXXXX"
  57         char *buf;
  58         const char *tmpdir;
  59
  60         tmpdir = NULL;
  61         if (issetugid() == 0)
  62                 tmpdir = getenv("TMPDIR");
  63         if (tmpdir == NULL)
  64                 tmpdir = _PATH_TMP;
  65
  66         if (*tmpdir == '\0')
  67                 return (NULL);
  68
  69         (void)asprintf(&buf, "%s%s%s", tmpdir,
  70             (tmpdir[strlen(tmpdir) - 1] == '/') ? "" : "/", TRAILER);
  71         if (buf == NULL)
  72                 return (NULL);
  73
  74         sigfillset(&set);
  75         (void)_sigprocmask(SIG_BLOCK, &set, &oset);
  76
  77         fd = mkstemp(buf);
  78         if (fd != -1)
  79                 (void)unlink(buf);
  80
  81         free(buf);
  82
  83         (void)_sigprocmask(SIG_SETMASK, &oset, NULL);
  84
  85         if (fd == -1)
  86                 return (NULL);
  87
  88         if ((fp = fdopen(fd, "w+")) == NULL) {
  89                 sverrno = errno;
  90                 (void)_close(fd);
  91                 errno = sverrno;
  92                 return (NULL);
  93         }
  94         return (fp);
  95 }