1 /*
2 * Copyright (c) 1985 Regents of the University of California.
3 * 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)
35 static char sccsid[] = "@(#)getusershell.c 5.7 (Berkeley) 2/23/91";
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 <ctype.h>
42 #include <stdio.h>
43 #include <stdlib.h>
44 #include <unistd.h>
45
46 #define SHELLS "/etc/shells"
47
48 /*
49 * Do not add local shells here. They should be added in /etc/shells
50 */
51 static char *okshells[] =
52 { "/bin/sh", "/bin/csh", 0 };
53
54 static char **shells, *strings;
55 static char **curshell = NULL;
56 static char **initshells();
57
58 /*
59 * Get a list of shells from SHELLS, if it exists.
60 */
61 char *
getusershell()62 getusershell()
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
74 void
endusershell()75 endusershell()
76 {
77
78 if (shells != NULL)
79 free((char *)shells);
80 shells = NULL;
81 if (strings != NULL)
82 free(strings);
83 strings = NULL;
84 curshell = NULL;
85 }
86
87 void
setusershell()88 setusershell()
89 {
90
91 curshell = initshells();
92 }
93
94 static char **
initshells()95 initshells()
96 {
97 register char **sp, *cp;
98 register FILE *fp;
99 struct stat statb;
100
101 if (shells != NULL)
102 free((char *)shells);
103 shells = NULL;
104 if (strings != NULL)
105 free(strings);
106 strings = NULL;
107 if ((fp = fopen(SHELLS, "r")) == (FILE *)0)
108 return(okshells);
109 if (fstat(fileno(fp), &statb) == -1) {
110 (void)fclose(fp);
111 return(okshells);
112 }
113 if ((strings = malloc((unsigned)statb.st_size)) == NULL) {
114 (void)fclose(fp);
115 return(okshells);
116 }
117 shells = (char **)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, PATH_MAX + 1, fp) != NULL) {
127 while (*cp != '#' && *cp != '/' && *cp != '\0')
128 cp++;
129 if (*cp == '#' || *cp == '\0')
130 continue;
131 *sp++ = cp;
132 while (!isspace(*cp) && *cp != '#' && *cp != '\0')
133 cp++;
134 *cp++ = '\0';
135 }
136 *sp = (char *)0;
137 (void)fclose(fp);
138 return (shells);
139 }
140