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 2006 Sun Microsystems, Inc. All rights reserved.
24 * Use is subject to license terms.
25 */
26
27 /* Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T */
28
29 #include <sys/param.h>
30 #include <sys/types.h>
31 #include <sys/sysmacros.h>
32 #include <sys/systm.h>
33 #include <sys/errno.h>
34 #include <sys/proc.h>
35 #include <sys/procset.h>
36 #include <sys/fault.h>
37 #include <sys/signal.h>
38 #include <sys/siginfo.h>
39 #include <sys/debug.h>
40
41 extern rctl_hndl_t rc_process_sigqueue;
42
43 static int
44 sigqkill(pid_t pid, sigsend_t *sigsend)
45 {
46 proc_t *p;
47 int error;
48
49 if ((uint_t)sigsend->sig >= NSIG)
50 return (EINVAL);
51
52 if (pid == -1) {
53 procset_t set;
54
55 setprocset(&set, POP_AND, P_ALL, P_MYID, P_ALL, P_MYID);
56 error = sigsendset(&set, sigsend);
57 } else if (pid > 0) {
58 mutex_enter(&pidlock);
59 if ((p = prfind(pid)) == NULL || p->p_stat == SIDL)
60 error = ESRCH;
61 else {
62 error = sigsendproc(p, sigsend);
63 if (error == 0 && sigsend->perm == 0)
64 error = EPERM;
65 }
66 mutex_exit(&pidlock);
67 } else {
68 int nfound = 0;
69 pid_t pgid;
70
71 if (pid == 0)
72 pgid = ttoproc(curthread)->p_pgrp;
73 else
74 pgid = -pid;
75
76 error = 0;
77 mutex_enter(&pidlock);
78 for (p = pgfind(pgid); p && !error; p = p->p_pglink) {
79 if (p->p_stat != SIDL) {
80 nfound++;
81 error = sigsendproc(p, sigsend);
82 }
83 }
84 mutex_exit(&pidlock);
85 if (nfound == 0)
86 error = ESRCH;
87 else if (error == 0 && sigsend->perm == 0)
88 error = EPERM;
89 }
90
91 return (error);
92 }
93
94
95 /*
96 * for implementations that don't require binary compatibility,
97 * the kill system call may be made into a library call to the
98 * sigsend system call
99 */
100 int
101 kill(pid_t pid, int sig)
102 {
103 int error;
104 sigsend_t v;
105
106 bzero(&v, sizeof (v));
107 v.sig = sig;
108 v.checkperm = 1;
109 v.sicode = SI_USER;
110 if ((error = sigqkill(pid, &v)) != 0)
111 return (set_errno(error));
112 return (0);
113 }
114
115 /*
116 * The handling of small unions, like the sigval argument to sigqueue,
117 * is architecture dependent. We have adopted the convention that the
118 * value itself is passed in the storage which crosses the kernel
119 * protection boundary. This procedure will accept a scalar argument,
120 * and store it in the appropriate value member of the sigsend_t structure.
121 */
122 int
123 sigqueue(pid_t pid, int sig, /* union sigval */ void *value,
124 int si_code, int block)
125 {
126 int error;
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(sig, si_code))
133 return (set_errno(EINVAL));
134
135 if ((sqh = p->p_sigqhdr) == NULL) {
136 rlim64_t sigqsz_max;
137
138 mutex_enter(&p->p_lock);
139 sigqsz_max = rctl_enforced_value(rc_process_sigqueue,
140 p->p_rctls, p);
141 mutex_exit(&p->p_lock);
142
143 /* Allocate sigqueue pool first time */
144 sqh = sigqhdralloc(sizeof (sigqueue_t), (uint_t)sigqsz_max);
145 mutex_enter(&p->p_lock);
146 if (p->p_sigqhdr == NULL) {
147 /* hang the pool head on proc */
148 p->p_sigqhdr = sqh;
149 } else {
150 /* another lwp allocated the pool, free ours */
151 sigqhdrfree(sqh);
152 sqh = p->p_sigqhdr;
153 }
154 mutex_exit(&p->p_lock);
155 }
156
157 do {
158 bzero(&v, sizeof (v));
159 v.sig = sig;
160 v.checkperm = 1;
161 v.sicode = si_code;
162 v.value.sival_ptr = value;
163 if ((error = sigqkill(pid, &v)) != EAGAIN || !block)
164 break;
165 /* block waiting for another chance to allocate a sigqueue_t */
166 mutex_enter(&sqh->sqb_lock);
167 while (sqh->sqb_count == 0) {
168 if (!cv_wait_sig(&sqh->sqb_cv, &sqh->sqb_lock)) {
169 error = EINTR;
170 break;
171 }
172 }
173 mutex_exit(&sqh->sqb_lock);
174 } while (error == EAGAIN);
175
176 if (error)
177 return (set_errno(error));
178 return (0);
179 }
180
181 #ifdef _SYSCALL32_IMPL
182 /*
183 * sigqueue32 - System call entry point for 32-bit callers on LP64 kernel,
184 * needed to handle the 32-bit sigvals as correctly as we can. We always
185 * assume that a 32-bit caller is passing an int. A 64-bit recipient
186 * that expects an int will therefore get it correctly. A 32-bit
187 * recipient will also get it correctly since siginfo_kto32() uses
188 * sival_int in the conversion. Since a 32-bit pointer has the same
189 * size and address in the sigval, it also converts correctly so that
190 * two 32-bit apps can exchange a pointer value. However, this means
191 * that a pointer sent by a 32-bit caller will be seen in the upper half
192 * by a 64-bit recipient, and only the upper half of a 64-bit pointer will
193 * be seen by a 32-bit recipient. This is the best solution that does
194 * not require severe hacking of the sigval union. Anyways, what it
195 * means to be sending pointers between processes with dissimilar
196 * models is unclear.
197 */
198 int
199 sigqueue32(pid_t pid, int sig, /* union sigval32 */ caddr32_t value,
200 int si_code, int block)
201 {
202 union sigval sv;
203
204 bzero(&sv, sizeof (sv));
205 sv.sival_int = (int)value;
206 return (sigqueue(pid, sig, sv.sival_ptr, si_code, block));
207 }
208 #endif