xref: /haiku/src/system/libroot/posix/stdlib/mktemp.c (revision 1deede7388b04dbeec5af85cae7164735ea9e70d)
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 <sys/types.h>
35 #include <sys/stat.h>
36 #include <sys/time.h>
37 #include <fcntl.h>
38 #include <errno.h>
39 #include <stdio.h>
40 #include <stdlib.h>
41 #include <string.h>
42 #include <ctype.h>
43 #include <unistd.h>
44 #include <stdint.h>
45 
46 #include <errno_private.h>
47 
48 
49 static int _gettemp(char *, int *, int, int);
50 
51 static const char padchar[] = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
52 
53 
54 int
55 mkstemps(char *path, int slen)
56 {
57 	int fd;
58 	return _gettemp(path, &fd, 0, slen) ? fd : -1;
59 }
60 
61 
62 int
63 mkstemp(char *path)
64 {
65 	int fd;
66 	if (_gettemp(path, &fd, 0, 0))
67 		return fd;
68 
69 	return -1;
70 }
71 
72 
73 char *
74 mkdtemp(path)
75 	char *path;
76 {
77 	return (_gettemp(path, (int *)NULL, 1, 0) ? path : (char *)NULL);
78 }
79 
80 
81 char *
82 mktemp(char *path)
83 {
84 	if (_gettemp(path, (int *)NULL, 0, 0))
85 		return path;
86 
87 	return NULL;
88 }
89 
90 
91 static int
92 _gettemp(char *path, int *doopen, int domkdir, int slen)
93 {
94 	char *start, *trv, *suffp;
95 	char *pad;
96 	struct stat sbuf;
97 	int rval;
98 	static unsigned int seed = 0;
99 
100 	if (doopen != NULL && domkdir) {
101 		__set_errno(EINVAL);
102 		return 0;
103 	}
104 
105 	for (trv = path; *trv != '\0'; ++trv)
106 		;
107 
108 	trv -= slen;
109 	suffp = trv;
110 	--trv;
111 	if (trv < path) {
112 		__set_errno(EINVAL);
113 		return 0;
114 	}
115 
116 	/* Fill space with random characters */
117 	if (seed == 0) {
118 		/* Select a pseudo-random seed on first call to avoid
119 		to generate the same sequence of pattern */
120 		struct timeval tv;
121 		gettimeofday(&tv, 0);
122 		seed = (getpid() << 16) ^ getuid() ^ tv.tv_sec ^ tv.tv_usec;
123 	}
124 	while (trv >= path && *trv == 'X') {
125 		uint32_t value = rand_r(&seed) % (sizeof(padchar) - 1);
126 		*trv-- = padchar[value];
127 	}
128 	start = trv + 1;
129 
130 	/*
131 	 * check the target directory.
132 	 */
133 	if (doopen != NULL || domkdir) {
134 		for (; trv > path; --trv) {
135 			if (*trv == '/') {
136 				*trv = '\0';
137 				rval = stat(path, &sbuf);
138 				*trv = '/';
139 				if (rval != 0)
140 					return 0;
141 				if (!S_ISDIR(sbuf.st_mode)) {
142 					__set_errno(ENOTDIR);
143 					return 0;
144 				}
145 				break;
146 			}
147 		}
148 	}
149 
150 	for (;;) {
151 		if (doopen) {
152 			if ((*doopen = open(path, O_CREAT|O_EXCL|O_RDWR, 0600)) >= 0)
153 				return 1;
154 			if (errno != EEXIST)
155 				return 0;
156 		} else if (domkdir) {
157 			if (mkdir(path, 0700) == 0)
158 				return 1;
159 			if (errno != EEXIST)
160 				return 0;
161 		} else if (lstat(path, &sbuf))
162 			return errno == ENOENT;
163 
164 		/* If we have a collision, cycle through the space of filenames */
165 		for (trv = start;;) {
166 			if (*trv == '\0' || trv == suffp)
167 				return 0;
168 			pad = strchr(padchar, *trv);
169 			if (pad == NULL || *++pad == '\0')
170 				*trv++ = padchar[0];
171 			else {
172 				*trv++ = *pad;
173 				break;
174 			}
175 		}
176 	}
177 
178 	/* not reached */
179 }
180