xref: /minix/external/bsd/nvi/dist/clib/mkstemp.c (revision 366d18b2)
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 #include "config.h"
35 
36 #if defined(LIBC_SCCS) && !defined(lint)
37 static const char sccsid[] = "@(#)mktemp.c	8.1 (Berkeley) 6/4/93";
38 #endif /* LIBC_SCCS and not lint */
39 #else
40 __RCSID("$NetBSD: mkstemp.c,v 1.2 2014/01/26 21:43:45 christos Exp $");
41 #endif
42 
43 #include <sys/types.h>
44 #include <sys/stat.h>
45 #include <fcntl.h>
46 #include <errno.h>
47 #include <stdio.h>
48 #include <ctype.h>
49 
50 static int _gettemp(char *path, register int *doopen);
51 
52 /*
53  * PUBLIC: #ifndef HAVE_MKSTEMP
54  * PUBLIC: int mkstemp __P((char *));
55  * PUBLIC: #endif
56  */
57 mkstemp(char *path)
58 {
59 	int fd;
60 
61 	return (_gettemp(path, &fd) ? fd : -1);
62 }
63 
64 char *
65 mktemp(char *path)
66 {
67 	return(_gettemp(path, (int *)NULL) ? path : (char *)NULL);
68 }
69 
70 static
71 _gettemp(char *path, register int *doopen)
72 {
73 	extern int errno;
74 	register char *start, *trv;
75 	struct stat sbuf;
76 	u_int pid;
77 
78 	pid = getpid();
79 	for (trv = path; *trv; ++trv);		/* extra X's get set to 0's */
80 	while (*--trv == 'X') {
81 		*trv = (pid % 10) + '0';
82 		pid /= 10;
83 	}
84 
85 	/*
86 	 * check the target directory; if you have six X's and it
87 	 * doesn't exist this runs for a *very* long time.
88 	 */
89 	for (start = trv + 1;; --trv) {
90 		if (trv <= path)
91 			break;
92 		if (*trv == '/') {
93 			*trv = '\0';
94 			if (stat(path, &sbuf))
95 				return(0);
96 			if (!S_ISDIR(sbuf.st_mode)) {
97 				errno = ENOTDIR;
98 				return(0);
99 			}
100 			*trv = '/';
101 			break;
102 		}
103 	}
104 
105 	for (;;) {
106 		if (doopen) {
107 			if ((*doopen =
108 			    open(path, O_CREAT|O_EXCL|O_RDWR, 0600)) >= 0)
109 				return(1);
110 			if (errno != EEXIST)
111 				return(0);
112 		}
113 		else if (stat(path, &sbuf))
114 			return(errno == ENOENT ? 1 : 0);
115 
116 		/* tricky little algorithm for backward compatibility */
117 		for (trv = start;;) {
118 			if (!*trv)
119 				return(0);
120 			if (*trv == 'z')
121 				*trv++ = 'a';
122 			else {
123 				if (isdigit(*trv))
124 					*trv = 'a';
125 				else
126 					++*trv;
127 				break;
128 			}
129 		}
130 	}
131 	/*NOTREACHED*/
132 }
133