xref: /freebsd/lib/libc/gen/getttyent.c (revision 396c556d77189a5c474d35cec6f44a762e310b7d)
1 /*-
2  * SPDX-License-Identifier: BSD-3-Clause
3  *
4  * Copyright (c) 1989, 1993
5  *	The Regents of the University of California.  All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  * 3. Neither the name of the University nor the names of its contributors
16  *    may be used to endorse or promote products derived from this software
17  *    without specific prior written permission.
18  *
19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29  * SUCH DAMAGE.
30  */
31 
32 #if defined(LIBC_SCCS) && !defined(lint)
33 static char sccsid[] = "@(#)getttyent.c	8.1 (Berkeley) 6/4/93";
34 #endif /* LIBC_SCCS and not lint */
35 #include <sys/cdefs.h>
36 __FBSDID("$FreeBSD$");
37 
38 #include <sys/types.h>
39 #include <sys/stat.h>
40 #include <sys/sysctl.h>
41 
42 #include <ctype.h>
43 #include <stdio.h>
44 #include <stdlib.h>
45 #include <string.h>
46 #include <ttyent.h>
47 
48 static char zapchar;
49 static FILE *tf;
50 static size_t lbsize;
51 static char *line;
52 
53 #define	MALLOCCHUNK	100
54 
55 static char *skip(char *);
56 static char *value(char *);
57 
58 struct ttyent *
59 getttynam(const char *tty)
60 {
61 	struct ttyent *t;
62 
63 	if (strncmp(tty, "/dev/", 5) == 0)
64 		tty += 5;
65 	setttyent();
66 	while ( (t = getttyent()) )
67 		if (!strcmp(tty, t->ty_name))
68 			break;
69 	endttyent();
70 	return (t);
71 }
72 
73 static int
74 auto_tty_status(const char *ty_name)
75 {
76 	size_t len;
77 	char *buf, *cons, *nextcons;
78 
79 	/* Check if this is an enabled kernel console line */
80 	buf = NULL;
81 	if (sysctlbyname("kern.console", NULL, &len, NULL, 0) == -1)
82 		return (0); /* Errors mean don't enable */
83 	buf = malloc(len);
84 	if (sysctlbyname("kern.console", buf, &len, NULL, 0) == -1)
85 		goto done;
86 
87 	if ((cons = strchr(buf, '/')) == NULL)
88 		goto done;
89 	*cons = '\0';
90 	nextcons = buf;
91 	while ((cons = strsep(&nextcons, ",")) != NULL && strlen(cons) != 0) {
92 		if (strcmp(cons, ty_name) == 0) {
93 			free(buf);
94 			return (TTY_ON);
95 		}
96 	}
97 
98 done:
99 	free(buf);
100 	return (0);
101 }
102 
103 static int
104 auto_exists_status(const char *ty_name)
105 {
106 	struct stat sb;
107 	char *dev;
108 	int rv;
109 
110 	rv = 0;
111 	if (*ty_name == '/')
112 		asprintf(&dev, "%s", ty_name);
113 	else
114 		asprintf(&dev, "/dev/%s", ty_name);
115 	if (dev != NULL && stat(dev, &sb) == 0)
116 		rv = TTY_ON;
117 	free(dev);
118 	return (rv);
119 }
120 
121 struct ttyent *
122 getttyent(void)
123 {
124 	static struct ttyent tty;
125 	char *p;
126 	int c;
127 	size_t i;
128 
129 	if (!tf && !setttyent())
130 		return (NULL);
131 	for (;;) {
132 		if (!fgets(p = line, lbsize, tf))
133 			return (NULL);
134 		/* extend buffer if line was too big, and retry */
135 		while (!strchr(p, '\n') && !feof(tf)) {
136 			i = strlen(p);
137 			lbsize += MALLOCCHUNK;
138 			if ((p = realloc(line, lbsize)) == NULL) {
139 				(void)endttyent();
140 				return (NULL);
141 			}
142 			line = p;
143 			if (!fgets(&line[i], lbsize - i, tf))
144 				return (NULL);
145 		}
146 		while (isspace((unsigned char)*p))
147 			++p;
148 		if (*p && *p != '#')
149 			break;
150 	}
151 
152 #define scmp(e) !strncmp(p, e, sizeof(e) - 1) && isspace((unsigned char)p[sizeof(e) - 1])
153 #define	vcmp(e)	!strncmp(p, e, sizeof(e) - 1) && p[sizeof(e) - 1] == '='
154 
155 	zapchar = 0;
156 	tty.ty_name = p;
157 	tty.ty_status = 0;
158 	tty.ty_window = NULL;
159 	tty.ty_group  = _TTYS_NOGROUP;
160 
161 	p = skip(p);
162 	if (!*(tty.ty_getty = p))
163 		tty.ty_getty = tty.ty_type = NULL;
164 	else {
165 		p = skip(p);
166 		if (!*(tty.ty_type = p))
167 			tty.ty_type = NULL;
168 		else {
169 			/* compatibility kludge: handle network/dialup specially */
170 			if (scmp(_TTYS_DIALUP))
171 				tty.ty_status |= TTY_DIALUP;
172 			else if (scmp(_TTYS_NETWORK))
173 				tty.ty_status |= TTY_NETWORK;
174 			p = skip(p);
175 		}
176 	}
177 
178 	for (; *p; p = skip(p)) {
179 		if (scmp(_TTYS_OFF))
180 			tty.ty_status &= ~TTY_ON;
181 		else if (scmp(_TTYS_ON))
182 			tty.ty_status |= TTY_ON;
183 		else if (scmp(_TTYS_ONIFCONSOLE))
184 			tty.ty_status |= auto_tty_status(tty.ty_name);
185 		else if (scmp(_TTYS_ONIFEXISTS))
186 			tty.ty_status |= auto_exists_status(tty.ty_name);
187 		else if (scmp(_TTYS_SECURE))
188 			tty.ty_status |= TTY_SECURE;
189 		else if (scmp(_TTYS_INSECURE))
190 			tty.ty_status &= ~TTY_SECURE;
191 		else if (scmp(_TTYS_DIALUP))
192 			tty.ty_status |= TTY_DIALUP;
193 		else if (scmp(_TTYS_NETWORK))
194 			tty.ty_status |= TTY_NETWORK;
195 		else if (vcmp(_TTYS_WINDOW))
196 			tty.ty_window = value(p);
197 		else if (vcmp(_TTYS_GROUP))
198 			tty.ty_group = value(p);
199 		else
200 			break;
201 	}
202 
203 	if (zapchar == '#' || *p == '#')
204 		while ((c = *++p) == ' ' || c == '\t')
205 			;
206 	tty.ty_comment = p;
207 	if (*p == 0)
208 		tty.ty_comment = 0;
209 	if ((p = strchr(p, '\n')))
210 		*p = '\0';
211 	return (&tty);
212 }
213 
214 #define	QUOTED	1
215 
216 /*
217  * Skip over the current field, removing quotes, and return a pointer to
218  * the next field.
219  */
220 static char *
221 skip(char *p)
222 {
223 	char *t;
224 	int c, q;
225 
226 	for (q = 0, t = p; (c = *p) != '\0'; p++) {
227 		if (c == '"') {
228 			q ^= QUOTED;	/* obscure, but nice */
229 			continue;
230 		}
231 		if (q == QUOTED && *p == '\\' && *(p+1) == '"')
232 			p++;
233 		*t++ = *p;
234 		if (q == QUOTED)
235 			continue;
236 		if (c == '#') {
237 			zapchar = c;
238 			*p = 0;
239 			break;
240 		}
241 		if (c == '\t' || c == ' ' || c == '\n') {
242 			zapchar = c;
243 			*p++ = 0;
244 			while ((c = *p) == '\t' || c == ' ' || c == '\n')
245 				p++;
246 			break;
247 		}
248 	}
249 	*--t = '\0';
250 	return (p);
251 }
252 
253 static char *
254 value(char *p)
255 {
256 
257 	return ((p = strchr(p, '=')) ? ++p : NULL);
258 }
259 
260 int
261 setttyent(void)
262 {
263 
264 	if (line == NULL) {
265 		if ((line = malloc(MALLOCCHUNK)) == NULL)
266 			return (0);
267 		lbsize = MALLOCCHUNK;
268 	}
269 	if (tf) {
270 		rewind(tf);
271 		return (1);
272 	} else if ( (tf = fopen(_PATH_TTYS, "re")) )
273 		return (1);
274 	return (0);
275 }
276 
277 int
278 endttyent(void)
279 {
280 	int rval;
281 
282 	/*
283          * NB: Don't free `line' because getttynam()
284 	 * may still be referencing it
285 	 */
286 	if (tf) {
287 		rval = (fclose(tf) != EOF);
288 		tf = NULL;
289 		return (rval);
290 	}
291 	return (1);
292 }
293 
294 static int
295 isttystat(const char *tty, int flag)
296 {
297 	struct ttyent *t;
298 
299 	return ((t = getttynam(tty)) == NULL) ? 0 : !!(t->ty_status & flag);
300 }
301 
302 
303 int
304 isdialuptty(const char *tty)
305 {
306 
307 	return isttystat(tty, TTY_DIALUP);
308 }
309 
310 int
311 isnettty(const char *tty)
312 {
313 
314 	return isttystat(tty, TTY_NETWORK);
315 }
316