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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 1.10 2006/07/28 02:17:40 dillon Exp $
39 * Error log buffer for kernel printf's.
42 #include <sys/param.h>
43 #include <sys/systm.h>
45 #include <sys/device.h>
47 #include <sys/vnode.h>
48 #include <sys/filio.h>
49 #include <sys/ttycom.h>
50 #include <sys/msgbuf.h>
51 #include <sys/signalvar.h>
52 #include <sys/kernel.h>
54 #include <sys/filedesc.h>
55 #include <sys/sysctl.h>
56 #include <sys/thread2.h>
58 #define LOG_ASYNC 0x04
59 #define LOG_RDWAIT 0x08
61 static d_open_t logopen;
62 static d_close_t logclose;
63 static d_read_t logread;
64 static d_ioctl_t logioctl;
65 static d_poll_t logpoll;
67 static void logtimeout(void *arg);
70 static struct dev_ops log_ops = {
71 { "log", CDEV_MAJOR, 0 },
79 static struct logsoftc {
80 int sc_state; /* see above for possibilities */
81 struct selinfo sc_selp; /* process waiting on select call */
82 struct sigio *sc_sigio; /* information for async I/O */
83 struct callout sc_callout; /* callout to wakeup syslog */
86 int log_open; /* also used in log() */
88 /* Times per second to check for a pending syslog wakeup. */
89 static int log_wakeups_per_second = 5;
90 SYSCTL_INT(_kern, OID_AUTO, log_wakeups_per_second, CTLFLAG_RW,
91 &log_wakeups_per_second, 0, "");
95 logopen(struct dev_open_args *ap)
97 struct proc *p = curproc;
103 callout_init(&logsoftc.sc_callout);
104 fsetown(p->p_pid, &logsoftc.sc_sigio); /* signal process only */
105 callout_reset(&logsoftc.sc_callout, hz / log_wakeups_per_second,
112 logclose(struct dev_close_args *ap)
115 callout_stop(&logsoftc.sc_callout);
116 logsoftc.sc_state = 0;
117 funsetown(logsoftc.sc_sigio);
123 logread(struct dev_read_args *ap)
125 struct uio *uio = ap->a_uio;
126 struct msgbuf *mbp = msgbufp;
131 while (mbp->msg_bufr == mbp->msg_bufx) {
132 if (ap->a_ioflag & IO_NDELAY) {
134 return (EWOULDBLOCK);
136 logsoftc.sc_state |= LOG_RDWAIT;
137 if ((error = tsleep((caddr_t)mbp, PCATCH, "klog", 0))) {
143 logsoftc.sc_state &= ~LOG_RDWAIT;
145 while (uio->uio_resid > 0) {
146 l = mbp->msg_bufx - mbp->msg_bufr;
148 l = mbp->msg_size - mbp->msg_bufr;
149 l = (long)szmin(l, uio->uio_resid);
152 error = uiomove((caddr_t)msgbufp->msg_ptr + mbp->msg_bufr,
157 if (mbp->msg_bufr >= mbp->msg_size)
165 logpoll(struct dev_poll_args *ap)
170 if (ap->a_events & (POLLIN | POLLRDNORM)) {
171 if (msgbufp->msg_bufr != msgbufp->msg_bufx)
172 revents |= ap->a_events & (POLLIN | POLLRDNORM);
174 selrecord(curthread, &logsoftc.sc_selp);
177 ap->a_events = revents;
182 logtimeout(void *arg)
187 if (msgbuftrigger == 0) {
188 callout_reset(&logsoftc.sc_callout,
189 hz / log_wakeups_per_second, logtimeout, NULL);
193 selwakeup(&logsoftc.sc_selp);
194 if ((logsoftc.sc_state & LOG_ASYNC) && logsoftc.sc_sigio != NULL)
195 pgsigio(logsoftc.sc_sigio, SIGIO, 0);
196 if (logsoftc.sc_state & LOG_RDWAIT) {
197 wakeup((caddr_t)msgbufp);
198 logsoftc.sc_state &= ~LOG_RDWAIT;
200 callout_reset(&logsoftc.sc_callout, hz / log_wakeups_per_second,
206 logioctl(struct dev_ioctl_args *ap)
212 /* return number of characters immediately available */
214 l = msgbufp->msg_bufx - msgbufp->msg_bufr;
217 l += msgbufp->msg_size;
218 *(int *)ap->a_data = l;
222 if (*(int *)ap->a_data)
223 logsoftc.sc_state |= LOG_ASYNC;
225 logsoftc.sc_state &= ~LOG_ASYNC;
229 return (fsetown(*(int *)ap->a_data, &logsoftc.sc_sigio));
232 *(int *)ap->a_data = fgetown(logsoftc.sc_sigio);
235 /* This is deprecated, FIOSETOWN should be used instead. */
237 return (fsetown(-(*(int *)ap->a_data), &logsoftc.sc_sigio));
239 /* This is deprecated, FIOGETOWN should be used instead */
241 *(int *)ap->a_data = -fgetown(logsoftc.sc_sigio);
251 log_drvinit(void *unused)
253 make_dev(&log_ops, 0, UID_ROOT, GID_WHEEL, 0600, "klog");
256 SYSINIT(logdev,SI_SUB_DRIVERS,SI_ORDER_MIDDLE+CDEV_MAJOR,log_drvinit,NULL)