getusershell.c revision 8870 
1/*
2 * Copyright (c) 1985, 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)
35static char sccsid[] = "@(#)getusershell.c	8.1 (Berkeley) 6/4/93";
36#endif /* LIBC_SCCS and not lint */
37
38#include <sys/param.h>
39#include <sys/file.h>
40#include <sys/stat.h>
41#include <stdio.h>
42#include <ctype.h>
43#include <stdlib.h>
44#include <unistd.h>
45#include <paths.h>
46
47/*
48 * Local shells should NOT be added here.  They should be added in
49 * /etc/shells.
50 */
51
52static char *okshells[] = { _PATH_BSHELL, _PATH_CSHELL, NULL };
53static char **curshell, **shells, *strings;
54static char **initshells __P((void));
55
56/*
57 * Get a list of shells from _PATH_SHELLS, if it exists.
58 */
59char *
60getusershell()
61{
62	char *ret;
63
64	if (curshell == NULL)
65		curshell = initshells();
66	ret = *curshell;
67	if (ret != NULL)
68		curshell++;
69	return (ret);
70}
71
72void
73endusershell()
74{
75
76	if (shells != NULL)
77		free(shells);
78	shells = NULL;
79	if (strings != NULL)
80		free(strings);
81	strings = NULL;
82	curshell = NULL;
83}
84
85void
86setusershell()
87{
88
89	curshell = initshells();
90}
91
92static char **
93initshells()
94{
95	register char **sp, *cp;
96	register FILE *fp;
97	struct stat statb;
98
99	if (shells != NULL)
100		free(shells);
101	shells = NULL;
102	if (strings != NULL)
103		free(strings);
104	strings = NULL;
105	if ((fp = fopen(_PATH_SHELLS, "r")) == NULL)
106		return (okshells);
107	if (fstat(fileno(fp), &statb) == -1) {
108		(void)fclose(fp);
109		return (okshells);
110	}
111	if ((strings = malloc((u_int)statb.st_size)) == NULL) {
112		(void)fclose(fp);
113		return (okshells);
114	}
115	shells = calloc((unsigned)statb.st_size / 3, sizeof (char *));
116	if (shells == NULL) {
117		(void)fclose(fp);
118		free(strings);
119		strings = NULL;
120		return (okshells);
121	}
122	sp = shells;
123	cp = strings;
124	while (fgets(cp, MAXPATHLEN + 1, fp) != NULL) {
125		while (*cp != '#' && *cp != '/' && *cp != '\0')
126			cp++;
127		if (*cp == '#' || *cp == '\0')
128			continue;
129		*sp++ = cp;
130		while (!isspace(*cp) && *cp != '#' && *cp != '\0')
131			cp++;
132		*cp++ = '\0';
133	}
134	*sp = NULL;
135	(void)fclose(fp);
136	return (shells);
137}
138