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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 1.2 2003/06/17 04:28:41 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_RDPRI (PZERO + 1)
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 cdevsw log_cdevsw = {
78 /* 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 proc *p)
108 callout_init(&logsoftc.sc_callout);
109 fsetown(p->p_pid, &logsoftc.sc_sigio); /* signal process only */
110 callout_reset(&logsoftc.sc_callout, hz / log_wakeups_per_second,
117 logclose(dev_t dev, int flag, int mode, struct proc *p)
121 callout_stop(&logsoftc.sc_callout);
122 logsoftc.sc_state = 0;
123 funsetown(logsoftc.sc_sigio);
129 logread(dev_t dev, struct uio *uio, int flag)
131 struct msgbuf *mbp = msgbufp;
137 while (mbp->msg_bufr == mbp->msg_bufx) {
138 if (flag & IO_NDELAY) {
140 return (EWOULDBLOCK);
142 logsoftc.sc_state |= LOG_RDWAIT;
143 if ((error = tsleep((caddr_t)mbp, LOG_RDPRI | PCATCH,
150 logsoftc.sc_state &= ~LOG_RDWAIT;
152 while (uio->uio_resid > 0) {
153 l = mbp->msg_bufx - mbp->msg_bufr;
155 l = mbp->msg_size - mbp->msg_bufr;
156 l = min(l, uio->uio_resid);
159 error = uiomove((caddr_t)msgbufp->msg_ptr + mbp->msg_bufr,
164 if (mbp->msg_bufr >= mbp->msg_size)
172 logpoll(dev_t dev, int events, struct proc *p)
179 if (events & (POLLIN | POLLRDNORM)) {
180 if (msgbufp->msg_bufr != msgbufp->msg_bufx)
181 revents |= events & (POLLIN | POLLRDNORM);
183 selrecord(p, &logsoftc.sc_selp);
190 logtimeout(void *arg)
195 if (msgbuftrigger == 0) {
196 callout_reset(&logsoftc.sc_callout,
197 hz / log_wakeups_per_second, logtimeout, NULL);
201 selwakeup(&logsoftc.sc_selp);
202 if ((logsoftc.sc_state & LOG_ASYNC) && logsoftc.sc_sigio != NULL)
203 pgsigio(logsoftc.sc_sigio, SIGIO, 0);
204 if (logsoftc.sc_state & LOG_RDWAIT) {
205 wakeup((caddr_t)msgbufp);
206 logsoftc.sc_state &= ~LOG_RDWAIT;
208 callout_reset(&logsoftc.sc_callout, hz / log_wakeups_per_second,
214 logioctl(dev_t dev, u_long com, caddr_t data, int flag, struct proc *p)
221 /* return number of characters immediately available */
224 l = msgbufp->msg_bufx - msgbufp->msg_bufr;
227 l += msgbufp->msg_size;
236 logsoftc.sc_state |= LOG_ASYNC;
238 logsoftc.sc_state &= ~LOG_ASYNC;
242 return (fsetown(*(int *)data, &logsoftc.sc_sigio));
245 *(int *)data = fgetown(logsoftc.sc_sigio);
248 /* This is deprecated, FIOSETOWN should be used instead. */
250 return (fsetown(-(*(int *)data), &logsoftc.sc_sigio));
252 /* This is deprecated, FIOGETOWN should be used instead */
254 *(int *)data = -fgetown(logsoftc.sc_sigio);
264 log_drvinit(void *unused)
267 make_dev(&log_cdevsw, 0, UID_ROOT, GID_WHEEL, 0600, "klog");
270 SYSINIT(logdev,SI_SUB_DRIVERS,SI_ORDER_MIDDLE+CDEV_MAJOR,log_drvinit,NULL)