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root/usr/lib/libc/stdio/mktemp.c

DEFINITIONS

1. mkstemp
2. mktemp
3. _gettemp

   1 /*
   2  * Copyright (c) 1987, 1993
   3  *      The Regents of the University of California.  All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  * 3. Neither the name of the University nor the names of its contributors
  14  *    may be used to endorse or promote products derived from this software
  15  *    without specific prior written permission.
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  27  * SUCH DAMAGE.
  28  */
  30 #include <sys/types.h>
  31 #include <sys/stat.h>
  32 #include <fcntl.h>
  33 #include <errno.h>
  34 #include <stdio.h>
  35 #include <ctype.h>
  36 #include <unistd.h>
  38 static int _gettemp(char *, int *);
  40 int
mkstemp(path)
  42         char *path;
  43 {
  44         int fd;
  46         return (_gettemp(path, &fd) ? fd : -1);
  47 }
  49 char *
mktemp(path)
  51         char *path;
  52 {
  53         return(_gettemp(path, (int *)NULL) ? path : (char *)NULL);
  54 }
  56 static int
_gettemp(path, doopen)
  58         char *path;
  59         int *doopen;
  60 {
  61         extern int errno;
  62         char *start, *trv;
  63         struct stat sbuf;
u_int pid;
pid = getpid();
  67         for (trv = path; *trv; ++trv);          /* extra X's get set to 0's */
  68         while (*--trv == 'X') {
  69                 *trv = (pid % 10) + '0';
pid /= 10;
  71         }
  73         /*
  74          * check the target directory; if you have six X's and it
  75          * doesn't exist this runs for a *very* long time.
  76          */
  77         for (start = trv + 1;; --trv) {
  78                 if (trv <= path)
  79                         break;
  80                 if (*trv == '/') {
  81                         *trv = '\0';
  82                         if (stat(path, &sbuf))
  83                                 return(0);
  84                         if (!S_ISDIR(sbuf.st_mode)) {
errno = ENOTDIR;
  86                                 return(0);
  87                         }
  88                         *trv = '/';
  89                         break;
  90                 }
  91         }
  93         for (;;) {
  94                 if (doopen) {
  95                         if ((*doopen =
open(path, O_CREAT|O_EXCL|O_RDWR, 0600)) >= 0)
  97                                 return(1);
  98                         if (errno != EEXIST)
  99                                 return(0);
 100                 }
 101                 else if (stat(path, &sbuf))
 102                         return(errno == ENOENT ? 1 : 0);
 104                 /* tricky little algorithm for backward compatibility */
 105                 for (trv = start;;) {
 106                         if (!*trv)
 107                                 return(0);
 108                         if (*trv == 'z')
 109                                 *trv++ = 'a';
 110                         else {
 111                                 if (isdigit((unsigned char)*trv))
 112                                         *trv = 'a';
 113                                 else
 114                                         ++*trv;
 115                                 break;
 116                         }
 117                 }
 118         }
 119         /*NOTREACHED*/
 120 }