1 | /* |
2 | * Copyright (c) 1997-2013 Apple Computer, Inc. All rights reserved. |
3 | * |
4 | * @APPLE_OSREFERENCE_LICENSE_HEADER_START@ |
5 | * |
6 | * This file contains Original Code and/or Modifications of Original Code |
7 | * as defined in and that are subject to the Apple Public Source License |
8 | * Version 2.0 (the 'License'). You may not use this file except in |
9 | * compliance with the License. The rights granted to you under the License |
10 | * may not be used to create, or enable the creation or redistribution of, |
11 | * unlawful or unlicensed copies of an Apple operating system, or to |
12 | * circumvent, violate, or enable the circumvention or violation of, any |
13 | * terms of an Apple operating system software license agreement. |
14 | * |
15 | * Please obtain a copy of the License at |
16 | * http://www.opensource.apple.com/apsl/ and read it before using this file. |
17 | * |
18 | * The Original Code and all software distributed under the License are |
19 | * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER |
20 | * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, |
21 | * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, |
22 | * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT. |
23 | * Please see the License for the specific language governing rights and |
24 | * limitations under the License. |
25 | * |
26 | * @APPLE_OSREFERENCE_LICENSE_HEADER_END@ |
27 | */ |
28 | /*- |
29 | * Copyright (c) 1982, 1986, 1991, 1993 |
30 | * The Regents of the University of California. All rights reserved. |
31 | * |
32 | * Redistribution and use in source and binary forms, with or without |
33 | * modification, are permitted provided that the following conditions |
34 | * are met: |
35 | * 1. Redistributions of source code must retain the above copyright |
36 | * notice, this list of conditions and the following disclaimer. |
37 | * 2. Redistributions in binary form must reproduce the above copyright |
38 | * notice, this list of conditions and the following disclaimer in the |
39 | * documentation and/or other materials provided with the distribution. |
40 | * 3. All advertising materials mentioning features or use of this software |
41 | * must display the following acknowledgement: |
42 | * This product includes software developed by the University of |
43 | * California, Berkeley and its contributors. |
44 | * 4. Neither the name of the University nor the names of its contributors |
45 | * may be used to endorse or promote products derived from this software |
46 | * without specific prior written permission. |
47 | * |
48 | * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND |
49 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
50 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
51 | * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE |
52 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
53 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
54 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
55 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
56 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
57 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
58 | * SUCH DAMAGE. |
59 | * |
60 | * @(#)tty_tty.c 8.2 (Berkeley) 9/23/93 |
61 | */ |
62 | |
63 | /* |
64 | * Indirect driver for controlling tty. |
65 | */ |
66 | #include <sys/param.h> |
67 | #include <sys/systm.h> |
68 | #include <sys/conf.h> |
69 | #include <sys/ioctl.h> |
70 | #include <sys/proc_internal.h> |
71 | #include <sys/tty.h> |
72 | #include <sys/vnode_internal.h> |
73 | #include <sys/file_internal.h> |
74 | #include <sys/kauth.h> |
75 | |
76 | /* Forward declarations for cdevsw[] entry */ |
77 | /* XXX we should consider making these static */ |
78 | int cttyopen(dev_t dev, int flag, int mode, proc_t p); |
79 | int cttyread(dev_t dev, struct uio *uio, int flag); |
80 | int cttywrite(dev_t dev, struct uio *uio, int flag); |
81 | int cttyioctl(dev_t dev, u_long cmd, caddr_t addr, int flag, proc_t p); |
82 | int cttyselect(dev_t dev, int flag, void* wql, proc_t p); |
83 | static vnode_t cttyvp(proc_t p); |
84 | |
85 | int |
86 | cttyopen(dev_t dev, int flag, __unused int mode, proc_t p) |
87 | { |
88 | vnode_t ttyvp = cttyvp(p); |
89 | struct vfs_context context; |
90 | int error = 0; |
91 | int cttyflag, doclose = 0; |
92 | struct session *sessp; |
93 | struct pgrp *pg; |
94 | |
95 | if (ttyvp == NULL) { |
96 | return ENXIO; |
97 | } |
98 | |
99 | context.vc_thread = current_thread(); |
100 | context.vc_ucred = kauth_cred_proc_ref(procp: p); |
101 | |
102 | pg = proc_pgrp(p, &sessp); |
103 | cttyflag = os_ref_get_raw_mask(rc: &sessp->s_refcount) & S_CTTYREF; |
104 | |
105 | /* |
106 | * A little hack--this device, used by many processes, |
107 | * happens to do an open on another device, which can |
108 | * cause unhappiness if the second-level open blocks indefinitely |
109 | * (as could be the case if the master side has hung up). Since |
110 | * we know that this driver doesn't care about the serializing |
111 | * opens and closes, we can drop the lock. To avoid opencount leak, |
112 | * open the vnode only for the first time. |
113 | */ |
114 | if (cttyflag == 0) { |
115 | devsw_unlock(dev, S_IFCHR); |
116 | error = VNOP_OPEN(ttyvp, flag, &context); |
117 | devsw_lock(dev, S_IFCHR); |
118 | |
119 | if (error) { |
120 | goto out; |
121 | } |
122 | |
123 | /* |
124 | * If S_CTTYREF is set, some other thread did an open |
125 | * and was able to set the flag, now perform a close, else |
126 | * set the flag. |
127 | */ |
128 | if (os_atomic_or_orig(&sessp->s_refcount, S_CTTYREF, relaxed) & S_CTTYREF) { |
129 | doclose = 1; |
130 | } |
131 | |
132 | /* |
133 | * We have to take a reference here to make sure a close |
134 | * gets called during revoke. Note that once a controlling |
135 | * tty gets opened by this driver, the only way close will |
136 | * get called is when the session leader , whose controlling |
137 | * tty is ttyvp, exits and vnode is revoked. We cannot |
138 | * redirect close from this driver because underlying controlling |
139 | * terminal might change and close may get redirected to a |
140 | * wrong vnode causing panic. |
141 | */ |
142 | if (doclose) { |
143 | devsw_unlock(dev, S_IFCHR); |
144 | VNOP_CLOSE(ttyvp, flag, &context); |
145 | devsw_lock(dev, S_IFCHR); |
146 | } else { |
147 | error = vnode_ref(vp: ttyvp); |
148 | } |
149 | } |
150 | |
151 | out: |
152 | pgrp_rele(pgrp: pg); |
153 | vnode_put(vp: ttyvp); |
154 | kauth_cred_unref(&context.vc_ucred); |
155 | |
156 | return error; |
157 | } |
158 | |
159 | int |
160 | cttyread(__unused dev_t dev, struct uio *uio, int flag) |
161 | { |
162 | vnode_t ttyvp = cttyvp(p: current_proc()); |
163 | struct vfs_context context; |
164 | int error; |
165 | |
166 | if (ttyvp == NULL) { |
167 | return EIO; |
168 | } |
169 | |
170 | context.vc_thread = current_thread(); |
171 | context.vc_ucred = NOCRED; |
172 | |
173 | error = VNOP_READ(vp: ttyvp, uio, ioflag: flag, ctx: &context); |
174 | vnode_put(vp: ttyvp); |
175 | |
176 | return error; |
177 | } |
178 | |
179 | int |
180 | cttywrite(__unused dev_t dev, struct uio *uio, int flag) |
181 | { |
182 | vnode_t ttyvp = cttyvp(p: current_proc()); |
183 | struct vfs_context context; |
184 | int error; |
185 | |
186 | if (ttyvp == NULL) { |
187 | return EIO; |
188 | } |
189 | |
190 | context.vc_thread = current_thread(); |
191 | context.vc_ucred = NOCRED; |
192 | |
193 | error = VNOP_WRITE(vp: ttyvp, uio, ioflag: flag, ctx: &context); |
194 | vnode_put(vp: ttyvp); |
195 | |
196 | return error; |
197 | } |
198 | |
199 | int |
200 | cttyioctl(__unused dev_t dev, u_long cmd, caddr_t addr, int flag, proc_t p) |
201 | { |
202 | vnode_t ttyvp = cttyvp(p: current_proc()); |
203 | struct vfs_context context; |
204 | int error = 0; |
205 | |
206 | if (ttyvp == NULL) { |
207 | return EIO; |
208 | } |
209 | if (cmd == TIOCSCTTY) { /* don't allow controlling tty to be set */ |
210 | error = EINVAL; /* to controlling tty -- infinite recursion */ |
211 | goto out; |
212 | } |
213 | if (cmd == TIOCNOTTY) { |
214 | struct pgrp *pg = proc_pgrp(p, NULL); |
215 | |
216 | if (!SESS_LEADER(p, pg->pg_session)) { |
217 | os_atomic_andnot(&p->p_flag, P_CONTROLT, relaxed); |
218 | error = 0; |
219 | } else { |
220 | error = EINVAL; |
221 | } |
222 | pgrp_rele(pgrp: pg); |
223 | goto out; |
224 | } |
225 | context.vc_thread = current_thread(); |
226 | context.vc_ucred = NOCRED; |
227 | |
228 | error = VNOP_IOCTL(vp: ttyvp, command: cmd, data: addr, fflag: flag, ctx: &context); |
229 | out: |
230 | vnode_put(vp: ttyvp); |
231 | return error; |
232 | } |
233 | |
234 | int |
235 | cttyselect(__unused dev_t dev, int flag, void* wql, __unused proc_t p) |
236 | { |
237 | vnode_t ttyvp = cttyvp(p: current_proc()); |
238 | struct vfs_context context; |
239 | int error; |
240 | |
241 | context.vc_thread = current_thread(); |
242 | context.vc_ucred = NOCRED; |
243 | |
244 | if (ttyvp == NULL) { |
245 | return 1; /* try operation to get EOF/failure */ |
246 | } |
247 | error = VNOP_SELECT(ttyvp, flag, FREAD | FWRITE, wql, &context); |
248 | vnode_put(vp: ttyvp); |
249 | return error; |
250 | } |
251 | |
252 | /* This returns vnode with ioref */ |
253 | static vnode_t |
254 | cttyvp(proc_t p) |
255 | { |
256 | struct pgrp *pg; |
257 | struct session *sessp; |
258 | vnode_t vp; |
259 | int vid; |
260 | |
261 | pg = proc_pgrp(p, &sessp); |
262 | |
263 | session_lock(sess: sessp); |
264 | vp = (p->p_flag & P_CONTROLT ? sessp->s_ttyvp : NULLVP); |
265 | vid = sessp->s_ttyvid; |
266 | if (vp) { |
267 | vnode_hold(vp); |
268 | } |
269 | session_unlock(sess: sessp); |
270 | |
271 | pgrp_rele(pgrp: pg); |
272 | |
273 | if (vp != NULLVP) { |
274 | /* cannot get an IO reference, return NULLVP */ |
275 | if (vnode_getwithvid(vp, vid) != 0) { |
276 | vnode_drop(vp); |
277 | vp = NULLVP; |
278 | } else { |
279 | vnode_drop(vp); |
280 | } |
281 | } |
282 | return vp; |
283 | } |
284 | |