BSD 4_3_Reno release

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

/*
* Copyright (c) 1987 Regents of the University of California.
* All rights reserved.
*
* Redistribution and use in source and binary forms are permitted
* provided that: (1) source distributions retain this entire copyright
* notice and comment, and (2) distributions including binaries display
* the following acknowledgement:  ``This product includes software
* developed by the University of California, Berkeley and its contributors''
* in the documentation or other materials provided with the distribution
* and in all advertising materials mentioning features or use of this
* software. 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 ``AS IS'' AND WITHOUT ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
*/

#if defined(LIBC_SCCS) && !defined(lint)
static char sccsid[] = "@(#)mktemp.c    5.9 (Berkeley) 6/1/90";
#endif /* LIBC_SCCS and not lint */

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

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*/
}