xref: /illumos-gate/usr/src/uts/common/os/pgrp.c (revision ddb365bfc9e868ad24ccdcb0dc91af18b10df082)
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, Version 1.0 only
6  * (the "License").  You may not use this file except in compliance
7  * with the License.
8  *
9  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10  * or http://www.opensolaris.org/os/licensing.
11  * See the License for the specific language governing permissions
12  * and limitations under the License.
13  *
14  * When distributing Covered Code, include this CDDL HEADER in each
15  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16  * If applicable, add the following below this CDDL HEADER, with the
17  * fields enclosed by brackets "[]" replaced with your own identifying
18  * information: Portions Copyright [yyyy] [name of copyright owner]
19  *
20  * CDDL HEADER END
21  */
22 /*	Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T	*/
23 /*	  All Rights Reserved  	*/
24 
25 
26 /*
27  * Copyright 2005 Sun Microsystems, Inc.  All rights reserved.
28  * Use is subject to license terms.
29  */
30 
31 #include <sys/types.h>
32 #include <sys/sysmacros.h>
33 #include <sys/param.h>
34 #include <sys/systm.h>
35 #include <sys/cred.h>
36 #include <sys/vnode.h>
37 #include <sys/errno.h>
38 #include <sys/user.h>
39 #include <sys/mount.h>
40 #include <sys/proc.h>
41 #include <sys/signal.h>
42 #include <sys/siginfo.h>
43 #include <sys/ucontext.h>
44 #include <sys/prsystm.h>
45 #include <sys/session.h>
46 #include <sys/stream.h>
47 #include <sys/strsubr.h>
48 #include <sys/debug.h>
49 
50 /*
51  * Return 1 if process pointed to by 'cp' has a parent that would
52  * prevent its process group from being orphaned, 0 otherwise
53  */
54 
55 static int
56 pglinked(cp)
57 	register proc_t *cp;
58 {
59 	register proc_t *pp;
60 
61 	ASSERT(MUTEX_HELD(&pidlock));
62 
63 	if ((pp = cp->p_parent) != NULL &&
64 	    pp->p_pgidp != cp->p_pgidp &&
65 	    pp->p_sessp == cp->p_sessp)
66 		return (1);
67 	return (0);
68 }
69 
70 /*
71  * Send the specified signal to all processes whose process group ID is
72  * equal to 'pgid'
73  */
74 
75 void
76 pgsignal(pidp, sig)
77 	register struct pid *pidp;
78 	int sig;
79 {
80 	register proc_t *prp;
81 
82 	mutex_enter(&pidlock);
83 	for (prp = pidp->pid_pglink; prp; prp = prp->p_pglink) {
84 		mutex_enter(&prp->p_lock);
85 		sigtoproc(prp, NULL, sig);
86 		mutex_exit(&prp->p_lock);
87 	}
88 	mutex_exit(&pidlock);
89 }
90 
91 /*
92  * similiar to pgsignal in function except that pidlock mutex is assumed
93  * to be held by the caller.
94  */
95 void
96 sigtopg(pidp, sig)
97 	register struct pid *pidp;
98 	int sig;
99 {
100 	register proc_t *prp;
101 
102 	ASSERT(MUTEX_HELD(&pidlock));
103 
104 	for (prp = pidp->pid_pglink; prp; prp = prp->p_pglink) {
105 		mutex_enter(&prp->p_lock);
106 		sigtoproc(prp, NULL, sig);
107 		mutex_exit(&prp->p_lock);
108 	}
109 }
110 
111 /*
112  * Add a process to a process group
113  */
114 
115 void
116 pgjoin(p, pgp)
117 	register proc_t *p;
118 	register struct pid *pgp;
119 {
120 	ASSERT(MUTEX_HELD(&pidlock));
121 
122 	p->p_pgidp = pgp;
123 
124 	if (pgp->pid_pglink == NULL) {
125 		ASSERT(pgp->pid_pgtail == NULL);
126 		p->p_ppglink = NULL;
127 		p->p_pglink = NULL;
128 		pgp->pid_pglink = p;
129 		pgp->pid_pgtail = p;
130 	} else 	{
131 		ASSERT(pgp->pid_pgtail != NULL);
132 		if (pglinked(p)) {
133 			p->p_ppglink = NULL;
134 			p->p_pglink = pgp->pid_pglink;
135 			pgp->pid_pglink->p_ppglink = p;
136 			pgp->pid_pglink = p;
137 		} else {
138 			p->p_ppglink = pgp->pid_pgtail;
139 			p->p_pglink = NULL;
140 			pgp->pid_pgtail->p_pglink = p;
141 			pgp->pid_pgtail = p;
142 		}
143 	}
144 
145 	if (pgp->pid_pglink == pgp->pid_pgtail) {
146 		PID_HOLD(pgp);
147 		if (pglinked(p))
148 			pgp->pid_pgorphaned = 0;
149 		else
150 			pgp->pid_pgorphaned = 1;
151 	} else if (pgp->pid_pgorphaned && pglinked(p))
152 		pgp->pid_pgorphaned = 0;
153 }
154 
155 void
156 pgexit(prp)
157 	proc_t *prp;
158 {
159 	register proc_t *p;
160 	register struct pid *pgp;
161 
162 	ASSERT(MUTEX_HELD(&pidlock));
163 
164 	pgp = prp->p_pgidp;
165 
166 	if (pgp->pid_pglink == prp) {
167 		ASSERT(prp->p_ppglink == NULL); /* must be at the front */
168 		pgp->pid_pglink = prp->p_pglink;
169 	}
170 	if (prp->p_ppglink) {
171 		prp->p_ppglink->p_pglink = prp->p_pglink;
172 	}
173 	if (prp->p_pglink) {
174 		prp->p_pglink->p_ppglink = prp->p_ppglink;
175 	}
176 	if (pgp->pid_pgtail == prp) {
177 		pgp->pid_pgtail = prp->p_ppglink;
178 	}
179 
180 	prp->p_pgidp = NULL;
181 	prp->p_pglink = NULL;
182 	prp->p_ppglink = NULL;
183 
184 	if ((p = pgp->pid_pglink) == NULL) {
185 		PID_RELE(pgp);
186 	} else if (pgp->pid_pgorphaned == 0) {
187 		do {
188 			if (pglinked(p)) {
189 				return;
190 			}
191 		} while ((p = p->p_pglink) != NULL);
192 		pgp->pid_pgorphaned = 1;
193 	}
194 }
195 
196 /*
197  * process 'pp' is exiting - check to see if this will
198  * orphan its children's process groups
199  */
200 
201 void
202 pgdetach(pp)
203 	proc_t *pp;
204 {
205 	int stopped;
206 	register proc_t *cp;
207 	register proc_t *mp;
208 	register struct pid *pgp;
209 
210 	ASSERT(MUTEX_HELD(&pidlock));
211 
212 	for (cp = pp->p_child; cp; cp = cp->p_sibling) {
213 		if ((pgp = cp->p_pgidp)->pid_pgorphaned)
214 			continue;
215 		stopped = 0;
216 		mp = pgp->pid_pglink;
217 		ASSERT(mp != NULL);
218 		for (;;) {
219 			if (mp != pp && mp->p_parent != pp && pglinked(mp))
220 				break;
221 			if (!stopped && mp != curproc) {
222 				mutex_enter(&mp->p_lock);
223 				stopped = jobstopped(mp);
224 				mutex_exit(&mp->p_lock);
225 			}
226 			if ((mp = mp->p_pglink) == NULL) {
227 				pgp->pid_pgorphaned = 1;
228 				if (stopped) {
229 					sigtopg(pgp, SIGHUP);
230 					sigtopg(pgp, SIGCONT);
231 				}
232 				break;
233 			}
234 		}
235 	}
236 }
237 
238 /*
239  * Return 1 if pgid is the process group ID of an existing process group
240  *	that has members not the process group leader in it.
241  *
242  * Otherwise, return 0.
243  */
244 
245 int
246 pgmembers(pgid)
247 	register pid_t pgid;
248 {
249 	register proc_t *prp;
250 
251 	ASSERT(MUTEX_HELD(&pidlock));
252 
253 	for (prp = pgfind(pgid); prp; prp = prp->p_pglink)
254 		if (prp->p_pid != pgid) {
255 			return (1);
256 		}
257 	return (0);
258 }
259