xref: /freebsd/lib/libc/gen/getttyent.c (revision 63f537551380d2dab29fa402ad1269feae17e594)
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 #include <sys/cdefs.h>
33 __SCCSID("@(#)getttyent.c	8.1 (Berkeley) 6/4/93");
34 #include <sys/types.h>
35 #include <sys/stat.h>
36 #include <sys/sysctl.h>
37 
38 #include <ctype.h>
39 #include <stdio.h>
40 #include <stdlib.h>
41 #include <string.h>
42 #include <ttyent.h>
43 
44 static char zapchar;
45 static FILE *tf;
46 static size_t lbsize;
47 static char *line;
48 
49 #define	MALLOCCHUNK	100
50 
51 static char *skip(char *);
52 static char *value(char *);
53 
54 struct ttyent *
55 getttynam(const char *tty)
56 {
57 	struct ttyent *t;
58 
59 	if (strncmp(tty, "/dev/", 5) == 0)
60 		tty += 5;
61 	setttyent();
62 	while ( (t = getttyent()) )
63 		if (!strcmp(tty, t->ty_name))
64 			break;
65 	endttyent();
66 	return (t);
67 }
68 
69 static int
70 auto_tty_status(const char *ty_name)
71 {
72 	size_t len;
73 	char *buf, *cons, *nextcons;
74 	int rv;
75 
76 	rv = TTY_IFCONSOLE;
77 
78 	/* Check if this is an enabled kernel console line */
79 	buf = NULL;
80 	if (sysctlbyname("kern.console", NULL, &len, NULL, 0) == -1)
81 		return (rv); /* Errors mean don't enable */
82 	buf = malloc(len);
83 	if (sysctlbyname("kern.console", buf, &len, NULL, 0) == -1)
84 		goto done;
85 
86 	if ((cons = strchr(buf, '/')) == NULL)
87 		goto done;
88 	*cons = '\0';
89 	nextcons = buf;
90 	while ((cons = strsep(&nextcons, ",")) != NULL && strlen(cons) != 0) {
91 		if (strcmp(cons, ty_name) == 0) {
92 			rv |= TTY_ON;
93 			break;
94 		}
95 	}
96 
97 done:
98 	free(buf);
99 	return (rv);
100 }
101 
102 static int
103 auto_exists_status(const char *ty_name)
104 {
105 	struct stat sb;
106 	char *dev;
107 	int rv;
108 
109 	rv = TTY_IFEXISTS;
110 	if (*ty_name == '/')
111 		asprintf(&dev, "%s", ty_name);
112 	else
113 		asprintf(&dev, "/dev/%s", ty_name);
114 	if (dev != NULL && stat(dev, &sb) == 0)
115 		rv |= TTY_ON;
116 	free(dev);
117 	return (rv);
118 }
119 
120 struct ttyent *
121 getttyent(void)
122 {
123 	static struct ttyent tty;
124 	char *p;
125 	int c;
126 	size_t i;
127 
128 	if (!tf && !setttyent())
129 		return (NULL);
130 	for (;;) {
131 		if (!fgets(p = line, lbsize, tf))
132 			return (NULL);
133 		/* extend buffer if line was too big, and retry */
134 		while (!strchr(p, '\n') && !feof(tf)) {
135 			i = strlen(p);
136 			lbsize += MALLOCCHUNK;
137 			if ((p = realloc(line, lbsize)) == NULL) {
138 				(void)endttyent();
139 				return (NULL);
140 			}
141 			line = p;
142 			if (!fgets(&line[i], lbsize - i, tf))
143 				return (NULL);
144 		}
145 		while (isspace((unsigned char)*p))
146 			++p;
147 		if (*p && *p != '#')
148 			break;
149 	}
150 
151 #define scmp(e) !strncmp(p, e, sizeof(e) - 1) && isspace((unsigned char)p[sizeof(e) - 1])
152 #define	vcmp(e)	!strncmp(p, e, sizeof(e) - 1) && p[sizeof(e) - 1] == '='
153 
154 	zapchar = 0;
155 	tty.ty_name = p;
156 	tty.ty_status = 0;
157 	tty.ty_window = NULL;
158 	tty.ty_group  = _TTYS_NOGROUP;
159 
160 	p = skip(p);
161 	if (!*(tty.ty_getty = p))
162 		tty.ty_getty = tty.ty_type = NULL;
163 	else {
164 		p = skip(p);
165 		if (!*(tty.ty_type = p))
166 			tty.ty_type = NULL;
167 		else {
168 			/* compatibility kludge: handle network/dialup specially */
169 			if (scmp(_TTYS_DIALUP))
170 				tty.ty_status |= TTY_DIALUP;
171 			else if (scmp(_TTYS_NETWORK))
172 				tty.ty_status |= TTY_NETWORK;
173 			p = skip(p);
174 		}
175 	}
176 
177 	for (; *p; p = skip(p)) {
178 		if (scmp(_TTYS_OFF))
179 			tty.ty_status &= ~TTY_ON;
180 		else if (scmp(_TTYS_ON))
181 			tty.ty_status |= TTY_ON;
182 		else if (scmp(_TTYS_ONIFCONSOLE))
183 			tty.ty_status |= auto_tty_status(tty.ty_name);
184 		else if (scmp(_TTYS_ONIFEXISTS))
185 			tty.ty_status |= auto_exists_status(tty.ty_name);
186 		else if (scmp(_TTYS_SECURE))
187 			tty.ty_status |= TTY_SECURE;
188 		else if (scmp(_TTYS_INSECURE))
189 			tty.ty_status &= ~TTY_SECURE;
190 		else if (scmp(_TTYS_DIALUP))
191 			tty.ty_status |= TTY_DIALUP;
192 		else if (scmp(_TTYS_NETWORK))
193 			tty.ty_status |= TTY_NETWORK;
194 		else if (vcmp(_TTYS_WINDOW))
195 			tty.ty_window = value(p);
196 		else if (vcmp(_TTYS_GROUP))
197 			tty.ty_group = value(p);
198 		else
199 			break;
200 	}
201 
202 	if (zapchar == '#' || *p == '#')
203 		while ((c = *++p) == ' ' || c == '\t')
204 			;
205 	tty.ty_comment = p;
206 	if (*p == 0)
207 		tty.ty_comment = 0;
208 	if ((p = strchr(p, '\n')))
209 		*p = '\0';
210 	return (&tty);
211 }
212 
213 #define	QUOTED	1
214 
215 /*
216  * Skip over the current field, removing quotes, and return a pointer to
217  * the next field.
218  */
219 static char *
220 skip(char *p)
221 {
222 	char *t;
223 	int c, q;
224 
225 	for (q = 0, t = p; (c = *p) != '\0'; p++) {
226 		if (c == '"') {
227 			q ^= QUOTED;	/* obscure, but nice */
228 			continue;
229 		}
230 		if (q == QUOTED && *p == '\\' && *(p+1) == '"')
231 			p++;
232 		*t++ = *p;
233 		if (q == QUOTED)
234 			continue;
235 		if (c == '#') {
236 			zapchar = c;
237 			*p = 0;
238 			break;
239 		}
240 		if (c == '\t' || c == ' ' || c == '\n') {
241 			zapchar = c;
242 			*p++ = 0;
243 			while ((c = *p) == '\t' || c == ' ' || c == '\n')
244 				p++;
245 			break;
246 		}
247 	}
248 	*--t = '\0';
249 	return (p);
250 }
251 
252 static char *
253 value(char *p)
254 {
255 
256 	return ((p = strchr(p, '=')) ? ++p : NULL);
257 }
258 
259 int
260 setttyent(void)
261 {
262 
263 	if (line == NULL) {
264 		if ((line = malloc(MALLOCCHUNK)) == NULL)
265 			return (0);
266 		lbsize = MALLOCCHUNK;
267 	}
268 	if (tf) {
269 		rewind(tf);
270 		return (1);
271 	} else if ( (tf = fopen(_PATH_TTYS, "re")) )
272 		return (1);
273 	return (0);
274 }
275 
276 int
277 endttyent(void)
278 {
279 	int rval;
280 
281 	/*
282          * NB: Don't free `line' because getttynam()
283 	 * may still be referencing it
284 	 */
285 	if (tf) {
286 		rval = (fclose(tf) != EOF);
287 		tf = NULL;
288 		return (rval);
289 	}
290 	return (1);
291 }
292 
293 static int
294 isttystat(const char *tty, int flag)
295 {
296 	struct ttyent *t;
297 
298 	return ((t = getttynam(tty)) == NULL) ? 0 : !!(t->ty_status & flag);
299 }
300 
301 
302 int
303 isdialuptty(const char *tty)
304 {
305 
306 	return isttystat(tty, TTY_DIALUP);
307 }
308 
309 int
310 isnettty(const char *tty)
311 {
312 
313 	return isttystat(tty, TTY_NETWORK);
314 }
315