BSD 4_3_Net_2 release

[unix-history] / usr / src / lib / libc / stdio / mktemp.c

/*
* Copyright (c) 1987 Regents of the University of California.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
*    notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
*    notice, this list of conditions and the following disclaimer in the
*    documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
*    must display the following acknowledgement:
*      This product includes software developed by the University of
*      California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
*    may be used to endorse or promote products derived from this software
*    without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/

#if defined(LIBC_SCCS) && !defined(lint)
static char sccsid[] = "@(#)mktemp.c    5.10 (Berkeley) 2/24/91";
#endif /* LIBC_SCCS and not lint */

#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <errno.h>
#include <stdio.h>

static int _gettemp();

mkstemp(path)
       char *path;
{
       int fd;

       return (_gettemp(path, &fd) ? fd : -1);
}

char *
mktemp(path)
       char *path;
{
       return(_gettemp(path, (int *)NULL) ? path : (char *)NULL);
}

static
_gettemp(path, doopen)
       char *path;
       register int *doopen;
{
       extern int errno;
       register char *start, *trv;
       struct stat sbuf;
       u_int pid;

       pid = getpid();
       for (trv = path; *trv; ++trv);          /* extra X's get set to 0's */
       while (*--trv == 'X') {
               *trv = (pid % 10) + '0';
               pid /= 10;
       }

       /*
        * check the target directory; if you have six X's and it
        * doesn't exist this runs for a *very* long time.
        */
       for (start = trv + 1;; --trv) {
               if (trv <= path)
                       break;
               if (*trv == '/') {
                       *trv = '\0';
                       if (stat(path, &sbuf))
                               return(0);
                       if (!S_ISDIR(sbuf.st_mode)) {
                               errno = ENOTDIR;
                               return(0);
                       }
                       *trv = '/';
                       break;
               }
       }

       for (;;) {
               if (doopen) {
                       if ((*doopen =
                           open(path, O_CREAT|O_EXCL|O_RDWR, 0600)) >= 0)
                               return(1);
                       if (errno != EEXIST)
                               return(0);
               }
               else if (stat(path, &sbuf))
                       return(errno == ENOENT ? 1 : 0);

               /* tricky little algorithm for backward compatibility */
               for (trv = start;;) {
                       if (!*trv)
                               return(0);
                       if (*trv == 'z')
                               *trv++ = 'a';
                       else {
                               if (isdigit(*trv))
                                       *trv = 'a';
                               else
                                       ++*trv;
                               break;
                       }
               }
       }
       /*NOTREACHED*/
}