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1.1 root 1: /*
2: * Copyright (c) 1982, 1986 Regents of the University of California.
3: * All rights reserved. The Berkeley software License Agreement
4: * specifies the terms and conditions for redistribution.
5: *
6: * @(#)subr_log.c 7.8 (Berkeley) 6/24/90
7: */
8:
9: /*
10: * Error log buffer for kernel printf's.
11: */
12:
13: #include "param.h"
14: #include "user.h"
15: #include "proc.h"
16: #include "vnode.h"
17: #include "ioctl.h"
18: #include "msgbuf.h"
19: #include "file.h"
20: #include "errno.h"
21:
22: #define LOG_RDPRI (PZERO + 1)
23:
24: #define LOG_ASYNC 0x04
25: #define LOG_RDWAIT 0x08
26:
27: struct logsoftc {
28: int sc_state; /* see above for possibilities */
29: struct proc *sc_selp; /* process waiting on select call */
30: int sc_pgid; /* process/group for async I/O */
31: } logsoftc;
32:
33: int log_open; /* also used in log() */
34:
35: /*ARGSUSED*/
36: logopen(dev)
37: dev_t dev;
38: {
39:
40: if (log_open)
41: return (EBUSY);
42: log_open = 1;
43: logsoftc.sc_pgid = u.u_procp->p_pid; /* signal process only */
44: /*
45: * Potential race here with putchar() but since putchar should be
46: * called by autoconf, msg_magic should be initialized by the time
47: * we get here.
48: */
49: if (msgbuf.msg_magic != MSG_MAGIC) {
50: register int i;
51:
52: msgbuf.msg_magic = MSG_MAGIC;
53: msgbuf.msg_bufx = msgbuf.msg_bufr = 0;
54: for (i=0; i < MSG_BSIZE; i++)
55: msgbuf.msg_bufc[i] = 0;
56: }
57: return (0);
58: }
59:
60: /*ARGSUSED*/
61: logclose(dev, flag)
62: dev_t dev;
63: {
64: log_open = 0;
65: logsoftc.sc_state = 0;
66: logsoftc.sc_selp = 0;
67: }
68:
69: /*ARGSUSED*/
70: logread(dev, uio, flag)
71: dev_t dev;
72: struct uio *uio;
73: int flag;
74: {
75: register long l;
76: register int s;
77: int error = 0;
78:
79: s = splhigh();
80: while (msgbuf.msg_bufr == msgbuf.msg_bufx) {
81: if (flag & IO_NDELAY) {
82: splx(s);
83: return (EWOULDBLOCK);
84: }
85: logsoftc.sc_state |= LOG_RDWAIT;
86: if (error = tsleep((caddr_t)&msgbuf, LOG_RDPRI | PCATCH,
87: "klog", 0)) {
88: splx(s);
89: return (error);
90: }
91: }
92: splx(s);
93: logsoftc.sc_state &= ~LOG_RDWAIT;
94:
95: while (uio->uio_resid > 0) {
96: l = msgbuf.msg_bufx - msgbuf.msg_bufr;
97: if (l < 0)
98: l = MSG_BSIZE - msgbuf.msg_bufr;
99: l = MIN(l, uio->uio_resid);
100: if (l == 0)
101: break;
102: error = uiomove((caddr_t)&msgbuf.msg_bufc[msgbuf.msg_bufr],
103: (int)l, uio);
104: if (error)
105: break;
106: msgbuf.msg_bufr += l;
107: if (msgbuf.msg_bufr < 0 || msgbuf.msg_bufr >= MSG_BSIZE)
108: msgbuf.msg_bufr = 0;
109: }
110: return (error);
111: }
112:
113: /*ARGSUSED*/
114: logselect(dev, rw)
115: dev_t dev;
116: int rw;
117: {
118: int s = splhigh();
119:
120: switch (rw) {
121:
122: case FREAD:
123: if (msgbuf.msg_bufr != msgbuf.msg_bufx) {
124: splx(s);
125: return (1);
126: }
127: logsoftc.sc_selp = u.u_procp;
128: break;
129: }
130: splx(s);
131: return (0);
132: }
133:
134: logwakeup()
135: {
136: struct proc *p;
137:
138: if (!log_open)
139: return;
140: if (logsoftc.sc_selp) {
141: selwakeup(logsoftc.sc_selp, 0);
142: logsoftc.sc_selp = 0;
143: }
144: if (logsoftc.sc_state & LOG_ASYNC) {
145: if (logsoftc.sc_pgid < 0)
146: gsignal(logsoftc.sc_pgid, SIGIO);
147: else if (p = pfind(logsoftc.sc_pgid))
148: psignal(p, SIGIO);
149: }
150: if (logsoftc.sc_state & LOG_RDWAIT) {
151: wakeup((caddr_t)&msgbuf);
152: logsoftc.sc_state &= ~LOG_RDWAIT;
153: }
154: }
155:
156: /*ARGSUSED*/
157: logioctl(dev, com, data, flag)
158: caddr_t data;
159: {
160: long l;
161: int s;
162:
163: switch (com) {
164:
165: /* return number of characters immediately available */
166: case FIONREAD:
167: s = splhigh();
168: l = msgbuf.msg_bufx - msgbuf.msg_bufr;
169: splx(s);
170: if (l < 0)
171: l += MSG_BSIZE;
172: *(off_t *)data = l;
173: break;
174:
175: case FIONBIO:
176: break;
177:
178: case FIOASYNC:
179: if (*(int *)data)
180: logsoftc.sc_state |= LOG_ASYNC;
181: else
182: logsoftc.sc_state &= ~LOG_ASYNC;
183: break;
184:
185: case TIOCSPGRP:
186: logsoftc.sc_pgid = *(int *)data;
187: break;
188:
189: case TIOCGPGRP:
190: *(int *)data = logsoftc.sc_pgid;
191: break;
192:
193: default:
194: return (-1);
195: }
196: return (0);
197: }
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