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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 $
38 * Error log buffer for kernel printf's.
41 #include <sys/param.h>
42 #include <sys/systm.h>
44 #include <sys/device.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>
52 #include <sys/event.h>
53 #include <sys/filedesc.h>
54 #include <sys/sysctl.h>
55 #include <sys/thread2.h>
57 #define LOG_ASYNC 0x04
58 #define LOG_RDWAIT 0x08
60 static d_open_t logopen;
61 static d_close_t logclose;
62 static d_read_t logread;
63 static d_ioctl_t logioctl;
64 static d_kqfilter_t logkqfilter;
66 static void logtimeout(void *arg);
67 static void logfiltdetach(struct knote *kn);
68 static int logfiltread(struct knote *kn, long hint);
71 static struct dev_ops log_ops = {
77 .d_kqfilter = logkqfilter
80 static struct logsoftc {
81 int sc_state; /* see above for possibilities */
82 struct kqinfo sc_kqp; /* processes waiting on I/O */
83 struct sigio *sc_sigio; /* information for async I/O */
84 struct callout sc_callout; /* callout to wakeup syslog */
87 int log_open; /* also used in log() */
89 /* Times per second to check for a pending syslog wakeup. */
90 static int log_wakeups_per_second = 5;
91 SYSCTL_INT(_kern, OID_AUTO, log_wakeups_per_second, CTLFLAG_RW,
92 &log_wakeups_per_second, 0, "");
96 logopen(struct dev_open_args *ap)
98 struct proc *p = curproc;
104 callout_init(&logsoftc.sc_callout);
105 fsetown(p->p_pid, &logsoftc.sc_sigio); /* signal process only */
106 callout_reset(&logsoftc.sc_callout, hz / log_wakeups_per_second,
113 logclose(struct dev_close_args *ap)
116 callout_stop(&logsoftc.sc_callout);
117 logsoftc.sc_state = 0;
118 funsetown(&logsoftc.sc_sigio);
124 logread(struct dev_read_args *ap)
126 struct uio *uio = ap->a_uio;
127 struct msgbuf *mbp = msgbufp;
132 while (mbp->msg_bufr == mbp->msg_bufx) {
133 if (ap->a_ioflag & IO_NDELAY) {
135 return (EWOULDBLOCK);
137 logsoftc.sc_state |= LOG_RDWAIT;
138 if ((error = tsleep((caddr_t)mbp, PCATCH, "klog", 0))) {
144 logsoftc.sc_state &= ~LOG_RDWAIT;
146 while (uio->uio_resid > 0) {
147 l = (long)mbp->msg_bufx - (long)mbp->msg_bufr;
149 l = mbp->msg_size - mbp->msg_bufr;
150 l = (long)szmin(l, uio->uio_resid);
153 error = uiomove((caddr_t)msgbufp->msg_ptr + mbp->msg_bufr,
158 if (mbp->msg_bufr >= mbp->msg_size)
164 static struct filterops logread_filtops =
165 { FILTEROP_ISFD, NULL, logfiltdetach, logfiltread };
168 logkqfilter(struct dev_kqfilter_args *ap)
170 struct knote *kn = ap->a_kn;
171 struct klist *klist = &logsoftc.sc_kqp.ki_note;
174 switch (kn->kn_filter) {
176 kn->kn_fop = &logread_filtops;
179 ap->a_result = EOPNOTSUPP;
183 knote_insert(klist, kn);
189 logfiltdetach(struct knote *kn)
191 struct klist *klist = &logsoftc.sc_kqp.ki_note;
193 knote_remove(klist, kn);
197 logfiltread(struct knote *kn, long hint)
202 if (msgbufp->msg_bufr != msgbufp->msg_bufx)
210 logtimeout(void *arg)
215 if (msgbuftrigger == 0) {
216 callout_reset(&logsoftc.sc_callout,
217 hz / log_wakeups_per_second, logtimeout, NULL);
221 KNOTE(&logsoftc.sc_kqp.ki_note, 0);
222 if ((logsoftc.sc_state & LOG_ASYNC) && logsoftc.sc_sigio != NULL)
223 pgsigio(logsoftc.sc_sigio, SIGIO, 0);
224 if (logsoftc.sc_state & LOG_RDWAIT) {
225 wakeup((caddr_t)msgbufp);
226 logsoftc.sc_state &= ~LOG_RDWAIT;
228 callout_reset(&logsoftc.sc_callout, hz / log_wakeups_per_second,
234 logioctl(struct dev_ioctl_args *ap)
240 /* return number of characters immediately available */
242 l = msgbufp->msg_bufx - msgbufp->msg_bufr;
245 l += msgbufp->msg_size;
246 *(int *)ap->a_data = l;
250 if (*(int *)ap->a_data)
251 logsoftc.sc_state |= LOG_ASYNC;
253 logsoftc.sc_state &= ~LOG_ASYNC;
257 return (fsetown(*(int *)ap->a_data, &logsoftc.sc_sigio));
260 *(int *)ap->a_data = fgetown(&logsoftc.sc_sigio);
263 /* This is deprecated, FIOSETOWN should be used instead. */
265 return (fsetown(-(*(int *)ap->a_data), &logsoftc.sc_sigio));
267 /* This is deprecated, FIOGETOWN should be used instead */
269 *(int *)ap->a_data = -fgetown(&logsoftc.sc_sigio);
279 log_drvinit(void *unused)
281 make_dev(&log_ops, 0, UID_ROOT, GID_WHEEL, 0600, "klog");
284 SYSINIT(logdev,SI_SUB_DRIVERS,SI_ORDER_MIDDLE+CDEV_MAJOR,log_drvinit,NULL)