xref: /minix3/lib/libc/stdio/mktemp.c (revision b706112487045bc1efd01e3d4d53d9a6b04a0bca)
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. All advertising materials mentioning features or use of this software
14  *    must display the following acknowledgement:
15  *	This product includes software developed by the University of
16  *	California, Berkeley and its contributors.
17  * 4. Neither the name of the University nor the names of its contributors
18  *    may be used to endorse or promote products derived from this software
19  *    without specific prior written permission.
20  *
21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31  * SUCH DAMAGE.
32  */
33 
34 #if defined(LIBC_SCCS) && !defined(lint)
35 static char sccsid[] = "@(#)mktemp.c	8.1 (Berkeley) 6/4/93";
36 #endif /* LIBC_SCCS and not lint */
37 
38 #include <sys/types.h>
39 #include <sys/stat.h>
40 #include <fcntl.h>
41 #include <errno.h>
42 #include <stdio.h>
43 #include <ctype.h>
44 #include <unistd.h>
45 #include <stdlib.h>
46 
47 static int _gettemp(char*,int*);
48 
49 mkstemp(path)
50 	char *path;
51 {
52 	int fd;
53 
54 	return (_gettemp(path, &fd) ? fd : -1);
55 }
56 
57 char *
58 mktemp(path)
59 	char *path;
60 {
61 	return(_gettemp(path, (int *)NULL) ? path : (char *)NULL);
62 }
63 
64 static
65 _gettemp(path, doopen)
66 	char *path;
67 	register int *doopen;
68 {
69 	extern int errno;
70 	register char *start, *trv;
71 	struct stat sbuf;
72 	u_int pid;
73 
74 	pid = getpid();
75 	for (trv = path; *trv; ++trv);		/* extra X's get set to 0's */
76 	while (*--trv == 'X') {
77 		*trv = (pid % 10) + '0';
78 		pid /= 10;
79 	}
80 
81 	/*
82 	 * check the target directory; if you have six X's and it
83 	 * doesn't exist this runs for a *very* long time.
84 	 */
85 	for (start = trv + 1;; --trv) {
86 		if (trv <= path)
87 			break;
88 		if (*trv == '/') {
89 			*trv = '\0';
90 			if (stat(path, &sbuf))
91 				return(0);
92 			if (!S_ISDIR(sbuf.st_mode)) {
93 				errno = ENOTDIR;
94 				return(0);
95 			}
96 			*trv = '/';
97 			break;
98 		}
99 	}
100 
101 	for (;;) {
102 		if (doopen) {
103 			if ((*doopen =
104 			    open(path, O_CREAT|O_EXCL|O_RDWR, 0600)) >= 0)
105 				return(1);
106 			if (errno != EEXIST)
107 				return(0);
108 		}
109 		else if (stat(path, &sbuf))
110 			return(errno == ENOENT ? 1 : 0);
111 
112 		/* tricky little algorithm for backward compatibility */
113 		for (trv = start;;) {
114 			if (!*trv)
115 				return(0);
116 			if (*trv == 'z')
117 				*trv++ = 'a';
118 			else {
119 				if (isdigit(*trv))
120 					*trv = 'a';
121 				else
122 					++*trv;
123 				break;
124 			}
125 		}
126 	}
127 	/*NOTREACHED*/
128 }
129 
130 /*
131  * $PchId: mktemp.c,v 1.3 1995/11/20 19:10:39 philip Exp $
132  */
133