xref: /titanic_41/usr/src/uts/common/syscall/sigqueue.c (revision 45916cd2fec6e79bca5dee0421bd39e3c2910d1e)
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 /*
23  * Copyright (c) 1998-2000 by Sun Microsystems, Inc.
24  * All rights reserved.
25  */
26 
27 /*	Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T	*/
28 
29 
30 
31 #pragma ident	"%Z%%M%	%I%	%E% SMI"
32 
33 #include <sys/param.h>
34 #include <sys/types.h>
35 #include <sys/sysmacros.h>
36 #include <sys/systm.h>
37 #include <sys/errno.h>
38 #include <sys/proc.h>
39 #include <sys/procset.h>
40 #include <sys/fault.h>
41 #include <sys/signal.h>
42 #include <sys/siginfo.h>
43 #include <sys/debug.h>
44 
45 static int
46 sigqkill(pid_t pid, int signo, sigsend_t *sigsend)
47 {
48 	register proc_t *p;
49 	int error;
50 
51 	if (signo < 0 || signo >= NSIG)
52 		return (set_errno(EINVAL));
53 
54 	if (pid == -1) {
55 		procset_t set;
56 
57 		setprocset(&set, POP_AND, P_ALL, P_MYID, P_ALL, P_MYID);
58 		error = sigsendset(&set, sigsend);
59 	} else if (pid > 0) {
60 		mutex_enter(&pidlock);
61 		if ((p = prfind(pid)) == NULL || p->p_stat == SIDL)
62 			error = ESRCH;
63 		else {
64 			error = sigsendproc(p, sigsend);
65 			if (error == 0 && sigsend->perm == 0)
66 				error = EPERM;
67 		}
68 		mutex_exit(&pidlock);
69 	} else {
70 		int nfound = 0;
71 		pid_t pgid;
72 
73 		if (pid == 0)
74 			pgid = ttoproc(curthread)->p_pgrp;
75 		else
76 			pgid = -pid;
77 
78 		error = 0;
79 		mutex_enter(&pidlock);
80 		for (p = pgfind(pgid); p && !error; p = p->p_pglink) {
81 			if (p->p_stat != SIDL) {
82 				nfound++;
83 				error = sigsendproc(p, sigsend);
84 			}
85 		}
86 		mutex_exit(&pidlock);
87 		if (nfound == 0)
88 			error = ESRCH;
89 		else if (error == 0 && sigsend->perm == 0)
90 			error = EPERM;
91 	}
92 
93 	if (error)
94 		return (set_errno(error));
95 	return (0);
96 }
97 
98 
99 /*
100  * for implementations that don't require binary compatibility,
101  * the kill system call may be made into a library call to the
102  * sigsend system call
103  */
104 int
105 kill(pid_t pid, int sig)
106 {
107 	sigsend_t v;
108 
109 	bzero(&v, sizeof (v));
110 	v.sig = sig;
111 	v.checkperm = 1;
112 	v.sicode = SI_USER;
113 
114 	return (sigqkill(pid, sig, &v));
115 }
116 
117 /*
118  * The handling of small unions, like the sigval argument to sigqueue,
119  * is architecture dependent.  We have adapted the convention that the
120  * value itself is passed in the storage which crosses the kernel
121  * protection boundary.  This procedure will accept a scalar argument,
122  * and store it in the appropriate value member of the sigsend_t structure.
123  */
124 int
125 sigqueue(pid_t pid, int signo, /* union sigval */ void *value, int si_code)
126 {
127 	sigsend_t v;
128 	sigqhdr_t *sqh;
129 	proc_t *p = curproc;
130 
131 	/* The si_code value must indicate the signal will be queued */
132 	if (pid <= 0 || !sigwillqueue(signo, si_code))
133 		return (set_errno(EINVAL));
134 
135 	if (p->p_sigqhdr == NULL) {
136 		/* Allocate sigqueue pool first time */
137 		sqh = sigqhdralloc(sizeof (sigqueue_t), _SIGQUEUE_MAX);
138 		mutex_enter(&p->p_lock);
139 		if (p->p_sigqhdr == NULL) {
140 			/* hang the pool head on proc */
141 			p->p_sigqhdr = sqh;
142 		} else {
143 			/* another lwp allocated the pool, free ours */
144 			sigqhdrfree(sqh);
145 		}
146 		mutex_exit(&p->p_lock);
147 	}
148 
149 	bzero(&v, sizeof (v));
150 	v.sig = signo;
151 	v.checkperm = 1;
152 	v.sicode = si_code;
153 	v.value.sival_ptr = value;
154 
155 	return (sigqkill(pid, signo, &v));
156 }
157 
158 #ifdef _SYSCALL32_IMPL
159 /*
160  * sigqueue32 - System call entry point for 32-bit callers on LP64 kernel,
161  * needed to handle the 32-bit sigvals as correctly as we can.  We always
162  * assume that a 32-bit caller is passing an int. A 64-bit recipient
163  * that expects an int will therefore get it correctly.  A 32-bit
164  * recipient will also get it correctly since siginfo_kto32() uses
165  * sival_int in the conversion.  Since a 32-bit pointer has the same
166  * size and address in the sigval, it also converts correctly so that
167  * two 32-bit apps can exchange a pointer value.  However, this means
168  * that a pointer sent by a 32-bit caller will be seen in the upper half
169  * by a 64-bit recipient, and only the upper half of a 64-bit pointer will
170  * be seen by a 32-bit recipient.  This is the best solution that does
171  * not require severe hacking of the sigval union.  Anyways, what it
172  * means to be sending pointers between processes with dissimilar
173  * models is unclear.
174  */
175 int
176 sigqueue32(pid_t pid, int signo, /* union sigval32 */ caddr32_t value,
177     int si_code)
178 {
179 	union sigval sv;
180 
181 	bzero(&sv, sizeof (sv));
182 	sv.sival_int = (int)value;
183 	return (sigqueue(pid, signo, sv.sival_ptr, si_code));
184 }
185 #endif
186