getusershell.c revision 52856 
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 * $FreeBSD: head/lib/libc/gen/getusershell.c 52856 1999-11-04 04:16:28Z ache $
34 */
35
36#if defined(LIBC_SCCS) && !defined(lint)
37static char sccsid[] = "@(#)getusershell.c	8.1 (Berkeley) 6/4/93";
38#endif /* LIBC_SCCS and not lint */
39
40#include <sys/param.h>
41#include <sys/file.h>
42#include <sys/stat.h>
43#include <stdio.h>
44#include <ctype.h>
45#include <stdlib.h>
46#include <unistd.h>
47#include <paths.h>
48
49/*
50 * Local shells should NOT be added here.  They should be added in
51 * /etc/shells.
52 */
53
54static char *okshells[] = { _PATH_BSHELL, _PATH_CSHELL, NULL };
55static char **curshell, **shells, *strings;
56static char **initshells __P((void));
57
58/*
59 * Get a list of shells from _PATH_SHELLS, if it exists.
60 */
61char *
62getusershell()
63{
64	char *ret;
65
66	if (curshell == NULL)
67		curshell = initshells();
68	ret = *curshell;
69	if (ret != NULL)
70		curshell++;
71	return (ret);
72}
73
74void
75endusershell()
76{
77
78	if (shells != NULL)
79		free(shells);
80	shells = NULL;
81	if (strings != NULL)
82		free(strings);
83	strings = NULL;
84	curshell = NULL;
85}
86
87void
88setusershell()
89{
90
91	curshell = initshells();
92}
93
94static char **
95initshells()
96{
97	register char **sp, *cp;
98	register FILE *fp;
99	struct stat statb;
100
101	if (shells != NULL)
102		free(shells);
103	shells = NULL;
104	if (strings != NULL)
105		free(strings);
106	strings = NULL;
107	if ((fp = fopen(_PATH_SHELLS, "r")) == NULL)
108		return (okshells);
109	if (fstat(fileno(fp), &statb) == -1) {
110		(void)fclose(fp);
111		return (okshells);
112	}
113	if ((strings = malloc((u_int)statb.st_size)) == NULL) {
114		(void)fclose(fp);
115		return (okshells);
116	}
117	shells = calloc((unsigned)statb.st_size / 3, sizeof (char *));
118	if (shells == NULL) {
119		(void)fclose(fp);
120		free(strings);
121		strings = NULL;
122		return (okshells);
123	}
124	sp = shells;
125	cp = strings;
126	while (fgets(cp, MAXPATHLEN + 1, fp) != NULL) {
127		while (*cp != '#' && *cp != '/' && *cp != '\0')
128			cp++;
129		if (*cp == '#' || *cp == '\0')
130			continue;
131		*sp++ = cp;
132		while (!isspace((unsigned char)*cp) && *cp != '#' && *cp != '\0')
133			cp++;
134		*cp++ = '\0';
135	}
136	*sp = NULL;
137	(void)fclose(fp);
138	return (shells);
139}
140