getusershell.c revision 55682 
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#ifdef HAVE_CONFIG_H
35#include <config.h>
36#endif
37
38RCSID("$Id: getusershell.c,v 1.8 1997/04/20 06:18:03 assar Exp $");
39
40#ifndef HAVE_GETUSERSHELL
41
42#include <stdio.h>
43#include <stdlib.h>
44#ifdef HAVE_PATHS_H
45#include <paths.h>
46#endif
47#ifdef HAVE_SYS_TYPES_H
48#include <sys/types.h>
49#endif
50#ifdef HAVE_SYS_STAT_H
51#include <sys/stat.h>
52#endif
53#ifdef HAVE_SYS_PARAM_H
54#include <sys/param.h>
55#endif
56
57#ifndef _PATH_SHELLS
58#define _PATH_SHELLS "/etc/shells"
59#endif
60
61#ifndef _PATH_BSHELL
62#define _PATH_BSHELL "/bin/sh"
63#endif
64
65#ifndef _PATH_CSHELL
66#define _PATH_CSHELL "/bin/csh"
67#endif
68
69/*
70 * Local shells should NOT be added here.  They should be added in
71 * /etc/shells.
72 */
73
74static char *okshells[] = { _PATH_BSHELL, _PATH_CSHELL, NULL };
75static char **curshell, **shells, *strings;
76static char **initshells (void);
77
78/*
79 * Get a list of shells from _PATH_SHELLS, if it exists.
80 */
81char *
82getusershell()
83{
84	char *ret;
85
86	if (curshell == NULL)
87		curshell = initshells();
88	ret = *curshell;
89	if (ret != NULL)
90		curshell++;
91	return (ret);
92}
93
94void
95endusershell()
96{
97
98	if (shells != NULL)
99		free(shells);
100	shells = NULL;
101	if (strings != NULL)
102		free(strings);
103	strings = NULL;
104	curshell = NULL;
105}
106
107void
108setusershell()
109{
110
111	curshell = initshells();
112}
113
114static char **
115initshells()
116{
117	char **sp, *cp;
118	FILE *fp;
119	struct stat statb;
120
121	if (shells != NULL)
122		free(shells);
123	shells = NULL;
124	if (strings != NULL)
125		free(strings);
126	strings = NULL;
127	if ((fp = fopen(_PATH_SHELLS, "r")) == NULL)
128		return (okshells);
129	if (fstat(fileno(fp), &statb) == -1) {
130		fclose(fp);
131		return (okshells);
132	}
133	if ((strings = malloc((u_int)statb.st_size)) == NULL) {
134		fclose(fp);
135		return (okshells);
136	}
137	shells = calloc((unsigned)statb.st_size / 3, sizeof (char *));
138	if (shells == NULL) {
139		fclose(fp);
140		free(strings);
141		strings = NULL;
142		return (okshells);
143	}
144	sp = shells;
145	cp = strings;
146	while (fgets(cp, MaxPathLen + 1, fp) != NULL) {
147		while (*cp != '#' && *cp != '/' && *cp != '\0')
148			cp++;
149		if (*cp == '#' || *cp == '\0')
150			continue;
151		*sp++ = cp;
152		while (!isspace(*cp) && *cp != '#' && *cp != '\0')
153			cp++;
154		*cp++ = '\0';
155	}
156	*sp = NULL;
157	fclose(fp);
158	return (shells);
159}
160#endif /* HAVE_GETUSERSHELL */
161