xref: /titanic_41/usr/src/common/util/getresponse.c (revision 110949431889689efc060068d11288e5c26032a6)
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  * Copyright 2007 Sun Microsystems, Inc.  All rights reserved.
23  * Use is subject to license terms.
24  */
25 
26 #include <stdio.h>
27 #include <string.h>
28 #include <stdlib.h>
29 #include <regex.h>
30 #include <locale.h>
31 #include <langinfo.h>
32 #include <limits.h>
33 #include <errno.h>
34 #include "getresponse.h"
35 
36 /* defaults - C locale values for yesstr, nostr, yesexpr (LC_MESSAGES) */
37 #define	DEFAULT_YESSTR  "yes"
38 #define	DEFAULT_NOSTR   "no"
39 #define	DEFAULT_YESEXPR "^[yY]"
40 #define	DEFAULT_NOEXPR	"^[nN]"
41 
42 #define	FREE_MEM        \
43 	if (yesstr)     \
44 		free(yesstr);   \
45 	if (nostr)      \
46 		free(nostr);    \
47 	if (yesexpr)    \
48 		free(yesexpr);  \
49 	if (noexpr)     \
50 		free(noexpr)
51 
52 #define	SET_DEFAULT_STRS \
53 	yesstr = DEFAULT_YESSTR; \
54 	nostr = DEFAULT_NOSTR; \
55 	yesexpr = DEFAULT_YESEXPR; \
56 	noexpr = DEFAULT_NOEXPR;
57 
58 /* variables used by getresponse functions */
59 char    *yesstr = NULL;
60 char    *nostr = NULL;
61 
62 /* for regcomp()/regexec() yesexpr and noexpr */
63 static regex_t preg_yes, preg_no;
64 
65 /*
66  * This function compiles a regular expression that is used to match an
67  * affirmative response from the user, and also assigns the strings used
68  * in the prompts that request affirmative or negative responses.  The
69  * locale's values for YESEXPR, NOEXPR, YESSTR and NOSTR are used.
70  *
71  * If there are any problems using the locale's YESEXPR, NOEXPR, YESSTR or NOSTR
72  * values, default values of YESEXPR, YESSTR and NOSTR will be used
73  * as a fallback.  The default values are the same as the C locale values.
74  */
75 int
init_yes(void)76 init_yes(void)
77 {
78 	int	fallback = 0;
79 	char    *yesexpr;
80 	char	*noexpr;
81 
82 	/* get yes expression and strings for yes/no prompts */
83 	yesstr  = strdup(nl_langinfo(YESSTR));
84 	nostr   = strdup(nl_langinfo(NOSTR));
85 	yesexpr = strdup(nl_langinfo(YESEXPR));
86 	noexpr  = strdup(nl_langinfo(NOEXPR));
87 
88 	if (yesstr == NULL || nostr == NULL ||
89 	    yesexpr == NULL || noexpr == NULL) {
90 		FREE_MEM;
91 		errno = ENOMEM;
92 		return (-1);
93 	}
94 
95 	/* if problem with locale strings, use default values */
96 	if (*yesstr == '\0' || *nostr == '\0' ||
97 	    *yesexpr == '\0' || *noexpr == '\0') {
98 		FREE_MEM;
99 		SET_DEFAULT_STRS;
100 		fallback = 1;
101 	}
102 	/* Compile the yes and no expressions */
103 	while (regcomp(&preg_yes, yesexpr, REG_EXTENDED | REG_NOSUB) != 0 ||
104 	    regcomp(&preg_no, noexpr, REG_EXTENDED | REG_NOSUB) != 0) {
105 		if (fallback == 1) {
106 			/* The fallback yesexpr failed, so exit */
107 			errno = EINVAL;
108 			return (-1);
109 		}
110 		/* The locale's yesexpr or noexpr failed so use fallback */
111 		FREE_MEM;
112 		SET_DEFAULT_STRS;
113 		fallback = 1;
114 	}
115 	return (0);
116 }
117 
118 static int
yes_no(int (* func)(char *))119 yes_no(int (*func)(char *))
120 {
121 	int	i, b;
122 	char    ans[LINE_MAX + 1];
123 
124 	/* Get user's answer */
125 	i = 0;
126 	for (;;) {
127 		b = getchar();
128 		if (b == '\n' || b == '\0' || b == EOF)
129 			break;
130 		if (i < LINE_MAX)
131 			ans[i] = b;
132 		i++;
133 	}
134 	if (i >= LINE_MAX)
135 		ans[LINE_MAX] = '\0';
136 	else
137 		ans[i] = '\0';
138 
139 	return (func(ans));
140 }
141 
142 static int
yes_no_check(char * ans,regex_t * reg1,regex_t * reg2)143 yes_no_check(char *ans, regex_t *reg1, regex_t *reg2)
144 {
145 	if (regexec(reg1, ans, 0, NULL, 0) == 0) {
146 		if (regexec(reg2, ans, 0, NULL, 0) == 0) {
147 			/* Both Expressions Match (reg2 conservative) */
148 			return (0);
149 		}
150 		/* Match */
151 		return (1);
152 	}
153 	return (0);
154 }
155 
156 /*
157  * yes_check() returns 1 if the input string is matched by yesexpr and is
158  * not matched by noexpr;  otherwise yes_check() returns 0.
159  */
160 int
yes_check(char * ans)161 yes_check(char *ans)
162 {
163 	return (yes_no_check(ans, &preg_yes, &preg_no));
164 }
165 
166 /*
167  * no_check() returns 1 if the input string is matched by noexpr and is
168  * not matched by yesexpr;  otherwise no_check() returns 0.
169  */
170 int
no_check(char * ans)171 no_check(char *ans)
172 {
173 	return (yes_no_check(ans, &preg_no, &preg_yes));
174 }
175 
176 int
yes(void)177 yes(void)
178 {
179 	return (yes_no(yes_check));
180 }
181 
182 int
no(void)183 no(void)
184 {
185 	return (yes_no(no_check));
186 }
187