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3 * The Regents of the University of California. All rights reserved.
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33 * @(#)subr_log.c 8.1 (Berkeley) 6/10/93
34 * $FreeBSD: src/sys/kern/subr_log.c,v 1.39.2.2 2001/06/02 08:11:25 phk Exp $
35 * $DragonFly: src/sys/kern/subr_log.c,v 1.7 2004/05/19 22:52:58 dillon Exp $
39 * Error log buffer for kernel printf's.
42 #include <sys/param.h>
43 #include <sys/systm.h>
46 #include <sys/vnode.h>
47 #include <sys/filio.h>
48 #include <sys/ttycom.h>
49 #include <sys/msgbuf.h>
50 #include <sys/signalvar.h>
51 #include <sys/kernel.h>
53 #include <sys/filedesc.h>
54 #include <sys/sysctl.h>
56 #define LOG_ASYNC 0x04
57 #define LOG_RDWAIT 0x08
59 static d_open_t logopen;
60 static d_close_t logclose;
61 static d_read_t logread;
62 static d_ioctl_t logioctl;
63 static d_poll_t logpoll;
65 static void logtimeout(void *arg);
68 static struct cdevsw log_cdevsw = {
82 /* strategy */ nostrategy,
87 static struct logsoftc {
88 int sc_state; /* see above for possibilities */
89 struct selinfo sc_selp; /* process waiting on select call */
90 struct sigio *sc_sigio; /* information for async I/O */
91 struct callout sc_callout; /* callout to wakeup syslog */
94 int log_open; /* also used in log() */
96 /* Times per second to check for a pending syslog wakeup. */
97 static int log_wakeups_per_second = 5;
98 SYSCTL_INT(_kern, OID_AUTO, log_wakeups_per_second, CTLFLAG_RW,
99 &log_wakeups_per_second, 0, "");
103 logopen(dev_t dev, int flags, int mode, struct thread *td)
105 struct proc *p = td->td_proc;
111 callout_init(&logsoftc.sc_callout);
112 fsetown(p->p_pid, &logsoftc.sc_sigio); /* signal process only */
113 callout_reset(&logsoftc.sc_callout, hz / log_wakeups_per_second,
120 logclose(dev_t dev, int flag, int mode, struct thread *td)
124 callout_stop(&logsoftc.sc_callout);
125 logsoftc.sc_state = 0;
126 funsetown(logsoftc.sc_sigio);
132 logread(dev_t dev, struct uio *uio, int flag)
134 struct msgbuf *mbp = msgbufp;
140 while (mbp->msg_bufr == mbp->msg_bufx) {
141 if (flag & IO_NDELAY) {
143 return (EWOULDBLOCK);
145 logsoftc.sc_state |= LOG_RDWAIT;
146 if ((error = tsleep((caddr_t)mbp, PCATCH, "klog", 0))) {
152 logsoftc.sc_state &= ~LOG_RDWAIT;
154 while (uio->uio_resid > 0) {
155 l = mbp->msg_bufx - mbp->msg_bufr;
157 l = mbp->msg_size - mbp->msg_bufr;
158 l = min(l, uio->uio_resid);
161 error = uiomove((caddr_t)msgbufp->msg_ptr + mbp->msg_bufr,
166 if (mbp->msg_bufr >= mbp->msg_size)
174 logpoll(dev_t dev, int events, struct thread *td)
181 if (events & (POLLIN | POLLRDNORM)) {
182 if (msgbufp->msg_bufr != msgbufp->msg_bufx)
183 revents |= events & (POLLIN | POLLRDNORM);
185 selrecord(td, &logsoftc.sc_selp);
192 logtimeout(void *arg)
197 if (msgbuftrigger == 0) {
198 callout_reset(&logsoftc.sc_callout,
199 hz / log_wakeups_per_second, logtimeout, NULL);
203 selwakeup(&logsoftc.sc_selp);
204 if ((logsoftc.sc_state & LOG_ASYNC) && logsoftc.sc_sigio != NULL)
205 pgsigio(logsoftc.sc_sigio, SIGIO, 0);
206 if (logsoftc.sc_state & LOG_RDWAIT) {
207 wakeup((caddr_t)msgbufp);
208 logsoftc.sc_state &= ~LOG_RDWAIT;
210 callout_reset(&logsoftc.sc_callout, hz / log_wakeups_per_second,
216 logioctl(dev_t dev, u_long com, caddr_t data, int flag, struct thread *td)
223 /* return number of characters immediately available */
226 l = msgbufp->msg_bufx - msgbufp->msg_bufr;
229 l += msgbufp->msg_size;
238 logsoftc.sc_state |= LOG_ASYNC;
240 logsoftc.sc_state &= ~LOG_ASYNC;
244 return (fsetown(*(int *)data, &logsoftc.sc_sigio));
247 *(int *)data = fgetown(logsoftc.sc_sigio);
250 /* This is deprecated, FIOSETOWN should be used instead. */
252 return (fsetown(-(*(int *)data), &logsoftc.sc_sigio));
254 /* This is deprecated, FIOGETOWN should be used instead */
256 *(int *)data = -fgetown(logsoftc.sc_sigio);
266 log_drvinit(void *unused)
268 cdevsw_add(&log_cdevsw, 0, 0);
269 make_dev(&log_cdevsw, 0, UID_ROOT, GID_WHEEL, 0600, "klog");
272 SYSINIT(logdev,SI_SUB_DRIVERS,SI_ORDER_MIDDLE+CDEV_MAJOR,log_drvinit,NULL)