xref: /illumos-gate/usr/src/lib/libc/port/gen/pt.c (revision 8e458de0baeb1fee50643403223bc7e909a48464)
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 /*
23  * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
24  * Use is subject to license terms.
25  */
26 
27 /*
28  * Copyright 2020 OmniOS Community Edition (OmniOSce) Association.
29  */
30 
31 /*	Copyright (c) 1988 AT&T	*/
32 /*	  All Rights Reserved	*/
33 
34 #pragma weak _ptsname = ptsname
35 #pragma weak _grantpt = grantpt
36 #pragma weak _unlockpt = unlockpt
37 
38 #include "lint.h"
39 #include "libc.h"
40 #include "mtlib.h"
41 #include <sys/types.h>
42 #include <signal.h>
43 #include <sys/param.h>
44 #include <sys/mkdev.h>
45 #include <sys/stream.h>
46 #include <sys/stropts.h>
47 #include <sys/wait.h>
48 #include <sys/signal.h>
49 #include <errno.h>
50 #include <fcntl.h>
51 #include <sys/stat.h>
52 #include <sys/ptms.h>
53 #include <string.h>
54 #include <stdlib.h>
55 #include <unistd.h>
56 #include <wait.h>
57 #include <spawn.h>
58 #include <grp.h>
59 #include "tsd.h"
60 
61 #define	PTSNAME "/dev/pts/"		/* slave name */
62 #define	PTLEN   32			/* slave name length */
63 #define	DEFAULT_TTY_GROUP	"tty"	/* slave device group owner */
64 
65 static void itoa(int, char *);
66 
67 /*
68  *  Check that fd argument is a file descriptor of an opened master.
69  *  Do this by sending an ISPTM ioctl message down stream. Ioctl()
70  *  will fail if:(1) fd is not a valid file descriptor.(2) the file
71  *  represented by fd does not understand ISPTM(not a master device).
72  *  If we have a valid master, get its minor number via fstat().
73  *  Concatenate it to PTSNAME and return it as the name of the slave
74  *  device.
75  */
76 static dev_t
77 ptsdev(int fd)
78 {
79 	struct stat64 status;
80 	struct strioctl istr;
81 
82 	istr.ic_cmd = ISPTM;
83 	istr.ic_len = 0;
84 	istr.ic_timout = 0;
85 	istr.ic_dp = NULL;
86 
87 	if (ioctl(fd, I_STR, &istr) < 0 || fstat64(fd, &status) < 0)
88 		return (NODEV);
89 
90 	return (minor(status.st_rdev));
91 }
92 
93 char *
94 ptsname(int fd)
95 {
96 	dev_t dev;
97 	char *sname;
98 
99 	if ((dev = ptsdev(fd)) == NODEV)
100 		return (NULL);
101 
102 	sname = tsdalloc(_T_PTSNAME, PTLEN, NULL);
103 	if (sname == NULL)
104 		return (NULL);
105 	(void) strcpy(sname, PTSNAME);
106 	itoa(dev, sname + strlen(PTSNAME));
107 
108 	/*
109 	 * This lookup will create the /dev/pts node (if the corresponding
110 	 * pty exists.
111 	 */
112 	if (access(sname, F_OK) ==  0)
113 		return (sname);
114 
115 	return (NULL);
116 }
117 
118 /*
119  * Send an ioctl down to the master device requesting the
120  * master/slave pair be unlocked.
121  */
122 int
123 unlockpt(int fd)
124 {
125 	struct strioctl istr;
126 
127 	istr.ic_cmd = UNLKPT;
128 	istr.ic_len = 0;
129 	istr.ic_timout = 0;
130 	istr.ic_dp = NULL;
131 
132 	if (ioctl(fd, I_STR, &istr) < 0)
133 		return (-1);
134 
135 	return (0);
136 }
137 
138 /*
139  * XPG4v2 requires that open of a slave pseudo terminal device
140  * provides the process with an interface that is identical to
141  * the terminal interface.
142  *
143  * To satisfy this, in strict XPG4v2 mode, this routine also sends
144  * a message down the stream that sets a flag in the kernel module
145  * so that additional actions are performed when opening an
146  * associated slave PTY device. When this happens, modules are
147  * automatically pushed onto the stream to provide terminal
148  * semantics and those modules are then informed that they should
149  * behave in strict XPG4v2 mode which modifies their behaviour. In
150  * particular, in strict XPG4v2 mode, empty blocks will be sent up
151  * the master side of the stream rather than being suppressed.
152  *
153  * Most applications do not expect this behaviour so it is only
154  * enabled for programs compiled in strict XPG4v2 mode (see
155  * stdlib.h).
156  */
157 int
158 __unlockpt_xpg4(int fd)
159 {
160 	int ret;
161 
162 	if ((ret = unlockpt(fd)) == 0) {
163 		struct strioctl istr;
164 
165 		istr.ic_cmd = PTSSTTY;
166 		istr.ic_len = 0;
167 		istr.ic_timout = 0;
168 		istr.ic_dp = NULL;
169 
170 		if (ioctl(fd, I_STR, &istr) < 0)
171 			ret = -1;
172 	}
173 
174 	return (ret);
175 }
176 
177 int
178 grantpt(int fd)
179 {
180 	struct strioctl istr;
181 	pt_own_t pto;
182 	struct group *gr_name;
183 
184 	/* validate the file descriptor before proceeding */
185 	if (ptsdev(fd) == NODEV)
186 		return (-1);
187 
188 	pto.pto_ruid = getuid();
189 
190 	gr_name = getgrnam(DEFAULT_TTY_GROUP);
191 	if (gr_name)
192 		pto.pto_rgid = gr_name->gr_gid;
193 	else
194 		pto.pto_rgid = getgid();
195 
196 	istr.ic_cmd = OWNERPT;
197 	istr.ic_len = sizeof (pt_own_t);
198 	istr.ic_timout = 0;
199 	istr.ic_dp = (char *)&pto;
200 
201 	if (ioctl(fd, I_STR, &istr) != 0) {
202 		errno = EACCES;
203 		return (-1);
204 	}
205 
206 	return (0);
207 }
208 
209 /*
210  * Send an ioctl down to the master device requesting the master/slave pair
211  * be assigned to the given zone.
212  */
213 int
214 zonept(int fd, zoneid_t zoneid)
215 {
216 	struct strioctl istr;
217 
218 	istr.ic_cmd = ZONEPT;
219 	istr.ic_len = sizeof (zoneid);
220 	istr.ic_timout = 0;
221 	istr.ic_dp = (char *)&zoneid;
222 
223 	if (ioctl(fd, I_STR, &istr) != 0) {
224 		return (-1);
225 	}
226 	return (0);
227 }
228 
229 
230 static void
231 itoa(int i, char *ptr)
232 {
233 	int dig = 0;
234 	int tempi;
235 
236 	tempi = i;
237 	do {
238 		dig++;
239 		tempi /= 10;
240 	} while (tempi);
241 
242 	ptr += dig;
243 	*ptr = '\0';
244 	while (--dig >= 0) {
245 		*(--ptr) = i % 10 + '0';
246 		i /= 10;
247 	}
248 }
249 
250 
251 /*
252  * added for SUSv3 standard
253  *
254  * Open a pseudo-terminal device.  External interface.
255  */
256 
257 int
258 posix_openpt(int oflag)
259 {
260 	return (open("/dev/ptmx", oflag));
261 }
262