xref: /illumos-gate/usr/src/lib/libc/port/stdio/tempnam.c (revision 7257d1b4)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or http://www.opensolaris.org/os/licensing.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  */
21 
22 /*
23  * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
24  * Use is subject to license terms.
25  */
26 
27 /*	Copyright (c) 1988 AT&T	*/
28 /*	  All Rights Reserved  	*/
29 
30 #pragma ident	"%Z%%M%	%I%	%E% SMI"
31 
32 #pragma weak _tempnam = tempnam
33 
34 #include "lint.h"
35 #include <mtlib.h>
36 #include <sys/types.h>
37 #include <stdio.h>
38 #include <string.h>
39 #include <stdlib.h>
40 #include <thread.h>
41 #include <synch.h>
42 #include <unistd.h>
43 #include <sys/stat.h>
44 
45 #define	max(A, B) (((A) < (B))?(B):(A))
46 
47 static char *pcopy(char *, const char *);
48 
49 static char seed[] = "AAA";
50 
51 static mutex_t seed_lk = DEFAULTMUTEX;
52 
53 char *
tempnam(const char * dir,const char * pfx)54 tempnam(const char *dir,	/* use this directory please (if non-NULL) */
55 	const char *pfx)	/* use this (if non-NULL) as filename prefix */
56 {
57 	char *p, *q, *tdir;
58 	size_t x = 0, y = 0, z;
59 	struct stat64 statbuf;
60 
61 	z = sizeof (P_tmpdir) - 1;
62 	if ((tdir = getenv("TMPDIR")) != NULL) {
63 		x = strlen(tdir);
64 	}
65 	if (dir != NULL) {
66 		if (stat64(dir, &statbuf) == 0 && S_ISDIR(statbuf.st_mode))
67 			y = strlen(dir);
68 	}
69 	if ((p = malloc(max(max(x, y), z)+16)) == NULL)
70 		return (NULL);
71 	if (x > 0 && access(pcopy(p, tdir), (W_OK | X_OK)) == 0)
72 		goto OK;
73 	if (y > 0 && access(pcopy(p, dir), (W_OK | X_OK)) == 0)
74 		goto OK;
75 	if (access(pcopy(p, P_tmpdir), (W_OK | X_OK)) == 0)
76 		goto OK;
77 	if (access(pcopy(p, "/tmp"), (W_OK | X_OK)) != 0) {
78 		free(p);
79 		return (NULL);
80 	}
81 OK:
82 	(void) strcat(p, "/");
83 	if (pfx) {
84 		*(p+strlen(p)+5) = '\0';
85 		(void) strncat(p, pfx, 5);
86 	}
87 	lmutex_lock(&seed_lk);
88 	(void) strcat(p, seed);
89 	(void) strcat(p, "XXXXXX");
90 	q = seed;
91 	while (*q == 'Z')
92 		*q++ = 'A';
93 	if (*q != '\0')
94 		++*q;
95 	lmutex_unlock(&seed_lk);
96 	if (*mktemp(p) == '\0') {
97 		free(p);
98 		return (NULL);
99 	}
100 	return (p);
101 }
102 
103 static char *
pcopy(char * space,const char * arg)104 pcopy(char *space, const char *arg)
105 {
106 	char *p;
107 
108 	if (arg) {
109 		(void) strcpy(space, arg);
110 		p = space-1+strlen(space);
111 		while ((p >= space) && (*p == '/'))
112 			*p-- = '\0';
113 	}
114 	return (space);
115 }
116