1 /*
2 * Copyright (c) 1991, 1993
3 * The Regents of the University of California. All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 * 3. Neither the name of the University nor the names of its contributors
14 * may be used to endorse or promote products derived from this software
15 * without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 *
29 * @(#)signalvar.h 8.6 (Berkeley) 2/19/95
30 * $FreeBSD: src/sys/sys/signalvar.h,v 1.34.2.1 2000/05/16 06:58:05 dillon Exp $
31 */
32
33 #ifndef _SYS_SIGNAL2_H_
34 #define _SYS_SIGNAL2_H_
35
36 #include <sys/param.h>
37 #include <sys/proc.h>
38 #include <sys/signalvar.h>
39
40 /*
41 * Inline functions:
42 */
43 /*
44 * Determine which signals are pending for a lwp.
45 *
46 * (Does not need to be interlocked with lwp_spin. If caller holds a
47 * critical section races will be resolved through an AST).
48 */
49 static __inline sigset_t
lwp_sigpend(struct lwp * lp)50 lwp_sigpend(struct lwp *lp)
51 {
52 sigset_t set;
53
54 set = lp->lwp_proc->p_siglist;
55 SIGSETOR(set, lp->lwp_siglist);
56
57 return (set);
58 }
59
60 /*
61 * Mark a signal as handled by the lwp.
62 *
63 * (p->p_token must be held, lp->lwp_spin must be held)
64 */
65 static __inline void
lwp_delsig(struct lwp * lp,int sig,int fromproc)66 lwp_delsig(struct lwp *lp, int sig, int fromproc)
67 {
68 SIGDELSET(lp->lwp_siglist, sig);
69 if (fromproc)
70 SIGDELSET_ATOMIC(lp->lwp_proc->p_siglist, sig);
71 }
72
73 #define CURSIG(lp) __cursig(lp, 1, 0, NULL)
74 #define CURSIG_TRACE(lp) __cursig(lp, 1, 1, NULL)
75 #define CURSIG_LCK_TRACE(lp, ptok) __cursig(lp, 1, 1, ptok)
76 #define CURSIG_NOBLOCK(lp) __cursig(lp, 0, 0, NULL)
77
78 /*
79 * This inline checks lpmap->blockallsigs, a user r/w accessible
80 * memory-mapped variable that allows a user thread to instantly
81 * mask and unmask all maskable signals without having to issue a
82 * system call.
83 *
84 * On the unmask count reaching 0, userland can check and clear
85 * bit 31 to determine if any signals arrived, then issue a dummy
86 * system call to ensure delivery.
87 */
88 static __inline
89 void
__sig_condblockallsigs(sigset_t * mask,struct lwp * lp)90 __sig_condblockallsigs(sigset_t *mask, struct lwp *lp)
91 {
92 struct sys_lpmap *lpmap;
93 uint32_t bas;
94 sigset_t tmp;
95 int trapsig;
96
97 if ((lpmap = lp->lwp_lpmap) == NULL)
98 return;
99
100 bas = lpmap->blockallsigs;
101 while (bas & 0x7FFFFFFFU) {
102 tmp = *mask; /* check maskable signals */
103 SIG_CANTMASK(tmp);
104 if (SIGISEMPTY(tmp)) /* no unmaskable signals */
105 return;
106
107 /*
108 * Upon successful update to lpmap->blockallsigs remove
109 * all maskable signals, leaving only unmaskable signals.
110 *
111 * If lwp_sig is non-zero it represents a syncronous 'trap'
112 * signal which, being a synchronous trap, must be allowed.
113 */
114 if (atomic_fcmpset_int(&lpmap->blockallsigs, &bas,
115 bas | 0x80000000U)) {
116 trapsig = lp->lwp_sig;
117 if (trapsig && SIGISMEMBER(*mask, trapsig)) {
118 SIGSETAND(*mask, sigcantmask_mask);
119 SIGADDSET(*mask, trapsig);
120 } else {
121 SIGSETAND(*mask, sigcantmask_mask);
122 }
123 break;
124 }
125 }
126 }
127
128 /*
129 * Determine signal that should be delivered to process p, the current
130 * process, 0 if none. If there is a pending stop signal with default
131 * action, the process stops in issignal().
132 *
133 * This function does not interlock pending signals. If the caller needs
134 * to interlock the caller must acquire the per-proc token.
135 *
136 * If ptok is non-NULL this function may return with proc->p_token held,
137 * indicating that the signal came from the process structure. This is
138 * used by postsig to avoid holding p_token when possible. Only applicable
139 * if mayblock is non-zero.
140 */
141 static __inline
142 int
__cursig(struct lwp * lp,int mayblock,int maytrace,int * ptok)143 __cursig(struct lwp *lp, int mayblock, int maytrace, int *ptok)
144 {
145 struct proc *p = lp->lwp_proc;
146 sigset_t tmpset;
147 int r;
148
149 tmpset = lwp_sigpend(lp);
150 SIGSETNAND(tmpset, lp->lwp_sigmask);
151 SIG_CONDBLOCKALLSIGS(tmpset, lp);
152
153 /* Nothing interesting happening? */
154 if (SIGISEMPTY(tmpset)) {
155 /*
156 * Quit here, unless
157 * a) we may block and
158 * b) somebody is tracing us.
159 */
160 if (mayblock == 0 || (p->p_flags & P_TRACED) == 0)
161 return (0);
162 }
163
164 if (mayblock)
165 r = issignal(lp, maytrace, ptok);
166 else
167 r = TRUE; /* simply state the fact */
168
169 return(r);
170 }
171
172 #endif /* !_SYS_SIGNAL2_H_ */
173