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4bcb762f WJ |
1 | /* |
2 | * Copyright (c) 1982, 1986 Regents of the University of California. | |
3 | * 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. All advertising materials mentioning features or use of this software | |
14 | * must display the following acknowledgement: | |
15 | * This product includes software developed by the University of | |
16 | * California, Berkeley and its contributors. | |
17 | * 4. Neither the name of the University nor the names of its contributors | |
18 | * may be used to endorse or promote products derived from this software | |
19 | * without specific prior written permission. | |
20 | * | |
21 | * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND | |
22 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE | |
23 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE | |
24 | * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE | |
25 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL | |
26 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS | |
27 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) | |
28 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT | |
29 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY | |
30 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF | |
31 | * SUCH DAMAGE. | |
32 | * | |
33 | * @(#)subr_log.c 7.11 (Berkeley) 3/17/91 | |
34 | */ | |
35 | ||
36 | /* | |
37 | * Error log buffer for kernel printf's. | |
38 | */ | |
39 | ||
40 | #include "param.h" | |
41 | #include "proc.h" | |
42 | #include "vnode.h" | |
43 | #include "ioctl.h" | |
44 | #include "msgbuf.h" | |
45 | #include "file.h" | |
46 | ||
47 | #define LOG_RDPRI (PZERO + 1) | |
48 | ||
49 | #define LOG_ASYNC 0x04 | |
50 | #define LOG_RDWAIT 0x08 | |
51 | ||
52 | struct logsoftc { | |
53 | int sc_state; /* see above for possibilities */ | |
54 | struct proc *sc_selp; /* process waiting on select call */ | |
55 | int sc_pgid; /* process/group for async I/O */ | |
56 | } logsoftc; | |
57 | ||
58 | int log_open; /* also used in log() */ | |
59 | ||
60 | /*ARGSUSED*/ | |
61 | logopen(dev, flags, mode, p) | |
62 | dev_t dev; | |
63 | int flags, mode; | |
64 | struct proc *p; | |
65 | { | |
66 | register struct msgbuf *mbp = msgbufp; | |
67 | ||
68 | if (log_open) | |
69 | return (EBUSY); | |
70 | log_open = 1; | |
71 | logsoftc.sc_pgid = p->p_pid; /* signal process only */ | |
72 | /* | |
73 | * Potential race here with putchar() but since putchar should be | |
74 | * called by autoconf, msg_magic should be initialized by the time | |
75 | * we get here. | |
76 | */ | |
77 | if (mbp->msg_magic != MSG_MAGIC) { | |
78 | register int i; | |
79 | ||
80 | mbp->msg_magic = MSG_MAGIC; | |
81 | mbp->msg_bufx = mbp->msg_bufr = 0; | |
82 | for (i=0; i < MSG_BSIZE; i++) | |
83 | mbp->msg_bufc[i] = 0; | |
84 | } | |
85 | return (0); | |
86 | } | |
87 | ||
88 | /*ARGSUSED*/ | |
89 | logclose(dev, flag) | |
90 | dev_t dev; | |
91 | { | |
92 | log_open = 0; | |
93 | logsoftc.sc_state = 0; | |
94 | logsoftc.sc_selp = 0; | |
95 | } | |
96 | ||
97 | /*ARGSUSED*/ | |
98 | logread(dev, uio, flag) | |
99 | dev_t dev; | |
100 | struct uio *uio; | |
101 | int flag; | |
102 | { | |
103 | register struct msgbuf *mbp = msgbufp; | |
104 | register long l; | |
105 | register int s; | |
106 | int error = 0; | |
107 | ||
108 | s = splhigh(); | |
109 | while (mbp->msg_bufr == mbp->msg_bufx) { | |
110 | if (flag & IO_NDELAY) { | |
111 | splx(s); | |
112 | return (EWOULDBLOCK); | |
113 | } | |
114 | logsoftc.sc_state |= LOG_RDWAIT; | |
115 | if (error = tsleep((caddr_t)mbp, LOG_RDPRI | PCATCH, | |
116 | "klog", 0)) { | |
117 | splx(s); | |
118 | return (error); | |
119 | } | |
120 | } | |
121 | splx(s); | |
122 | logsoftc.sc_state &= ~LOG_RDWAIT; | |
123 | ||
124 | while (uio->uio_resid > 0) { | |
125 | l = mbp->msg_bufx - mbp->msg_bufr; | |
126 | if (l < 0) | |
127 | l = MSG_BSIZE - mbp->msg_bufr; | |
128 | l = MIN(l, uio->uio_resid); | |
129 | if (l == 0) | |
130 | break; | |
131 | error = uiomove((caddr_t)&mbp->msg_bufc[mbp->msg_bufr], | |
132 | (int)l, uio); | |
133 | if (error) | |
134 | break; | |
135 | mbp->msg_bufr += l; | |
136 | if (mbp->msg_bufr < 0 || mbp->msg_bufr >= MSG_BSIZE) | |
137 | mbp->msg_bufr = 0; | |
138 | } | |
139 | return (error); | |
140 | } | |
141 | ||
142 | /*ARGSUSED*/ | |
143 | logselect(dev, rw, p) | |
144 | dev_t dev; | |
145 | int rw; | |
146 | struct proc *p; | |
147 | { | |
148 | int s = splhigh(); | |
149 | ||
150 | switch (rw) { | |
151 | ||
152 | case FREAD: | |
153 | if (msgbufp->msg_bufr != msgbufp->msg_bufx) { | |
154 | splx(s); | |
155 | return (1); | |
156 | } | |
157 | logsoftc.sc_selp = p; | |
158 | break; | |
159 | } | |
160 | splx(s); | |
161 | return (0); | |
162 | } | |
163 | ||
164 | logwakeup() | |
165 | { | |
166 | struct proc *p; | |
167 | ||
168 | if (!log_open) | |
169 | return; | |
170 | if (logsoftc.sc_selp) { | |
171 | selwakeup(logsoftc.sc_selp, 0); | |
172 | logsoftc.sc_selp = 0; | |
173 | } | |
174 | if (logsoftc.sc_state & LOG_ASYNC) { | |
175 | if (logsoftc.sc_pgid < 0) | |
176 | gsignal(-logsoftc.sc_pgid, SIGIO); | |
177 | else if (p = pfind(logsoftc.sc_pgid)) | |
178 | psignal(p, SIGIO); | |
179 | } | |
180 | if (logsoftc.sc_state & LOG_RDWAIT) { | |
181 | wakeup((caddr_t)msgbufp); | |
182 | logsoftc.sc_state &= ~LOG_RDWAIT; | |
183 | } | |
184 | } | |
185 | ||
186 | /*ARGSUSED*/ | |
187 | logioctl(dev, com, data, flag) | |
188 | caddr_t data; | |
189 | { | |
190 | long l; | |
191 | int s; | |
192 | ||
193 | switch (com) { | |
194 | ||
195 | /* return number of characters immediately available */ | |
196 | case FIONREAD: | |
197 | s = splhigh(); | |
198 | l = msgbufp->msg_bufx - msgbufp->msg_bufr; | |
199 | splx(s); | |
200 | if (l < 0) | |
201 | l += MSG_BSIZE; | |
202 | *(off_t *)data = l; | |
203 | break; | |
204 | ||
205 | case FIONBIO: | |
206 | break; | |
207 | ||
208 | case FIOASYNC: | |
209 | if (*(int *)data) | |
210 | logsoftc.sc_state |= LOG_ASYNC; | |
211 | else | |
212 | logsoftc.sc_state &= ~LOG_ASYNC; | |
213 | break; | |
214 | ||
215 | case TIOCSPGRP: | |
216 | logsoftc.sc_pgid = *(int *)data; | |
217 | break; | |
218 | ||
219 | case TIOCGPGRP: | |
220 | *(int *)data = logsoftc.sc_pgid; | |
221 | break; | |
222 | ||
223 | default: | |
224 | return (-1); | |
225 | } | |
226 | return (0); | |
227 | } |