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33 * @(#)subr_log.c 8.1 (Berkeley) 6/10/93
38 * Error log buffer for kernel printf's.
41 #include <sys/param.h>
42 #include <sys/systm.h>
45 #include <sys/vnode.h>
46 #include <sys/filio.h>
47 #include <sys/ttycom.h>
48 #include <sys/msgbuf.h>
49 #include <sys/signalvar.h>
50 #include <sys/kernel.h>
52 #include <sys/filedesc.h>
53 #include <sys/sysctl.h>
55 #define LOG_RDPRI (PZERO + 1)
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_poll_t logpoll;
66 static void logtimeout(void *arg);
69 static struct cdevsw log_cdevsw = {
77 /* strategy */ nostrategy,
85 static struct logsoftc {
86 int sc_state; /* see above for possibilities */
87 struct selinfo sc_selp; /* process waiting on select call */
88 struct sigio *sc_sigio; /* information for async I/O */
89 struct callout sc_callout; /* callout to wakeup syslog */
92 int log_open; /* also used in log() */
94 /* Times per second to check for a pending syslog wakeup. */
95 static int log_wakeups_per_second = 5;
96 SYSCTL_INT(_kern, OID_AUTO, log_wakeups_per_second, CTLFLAG_RW,
97 &log_wakeups_per_second, 0, "");
101 logopen(dev_t dev, int flags, int mode, struct thread *td)
106 callout_init(&logsoftc.sc_callout, 0);
107 fsetown(td->td_proc->p_pid, &logsoftc.sc_sigio); /* signal process only */
108 callout_reset(&logsoftc.sc_callout, hz / log_wakeups_per_second,
115 logclose(dev_t dev, int flag, int mode, struct thread *td)
119 callout_stop(&logsoftc.sc_callout);
120 logsoftc.sc_state = 0;
121 funsetown(&logsoftc.sc_sigio);
127 logread(dev_t dev, struct uio *uio, int flag)
129 struct msgbuf *mbp = msgbufp;
133 while (mbp->msg_bufr == mbp->msg_bufx) {
134 if (flag & IO_NDELAY) {
136 return (EWOULDBLOCK);
138 logsoftc.sc_state |= LOG_RDWAIT;
139 if ((error = tsleep(mbp, LOG_RDPRI | PCATCH, "klog", 0))) {
145 logsoftc.sc_state &= ~LOG_RDWAIT;
147 while (uio->uio_resid > 0) {
148 l = mbp->msg_bufx - mbp->msg_bufr;
150 l = mbp->msg_size - mbp->msg_bufr;
151 l = imin(l, uio->uio_resid);
154 error = uiomove((caddr_t)msgbufp->msg_ptr + mbp->msg_bufr,
159 if (mbp->msg_bufr >= mbp->msg_size)
167 logpoll(dev_t dev, int events, struct thread *td)
174 if (events & (POLLIN | POLLRDNORM)) {
175 if (msgbufp->msg_bufr != msgbufp->msg_bufx)
176 revents |= events & (POLLIN | POLLRDNORM);
178 selrecord(td, &logsoftc.sc_selp);
185 logtimeout(void *arg)
190 if (msgbuftrigger == 0) {
191 callout_reset(&logsoftc.sc_callout,
192 hz / log_wakeups_per_second, logtimeout, NULL);
196 selwakeup(&logsoftc.sc_selp);
197 if ((logsoftc.sc_state & LOG_ASYNC) && logsoftc.sc_sigio != NULL)
198 pgsigio(&logsoftc.sc_sigio, SIGIO, 0);
199 if (logsoftc.sc_state & LOG_RDWAIT) {
200 wakeup((caddr_t)msgbufp);
201 logsoftc.sc_state &= ~LOG_RDWAIT;
203 callout_reset(&logsoftc.sc_callout, hz / log_wakeups_per_second,
209 logioctl(dev_t dev, u_long com, caddr_t data, int flag, struct thread *td)
215 /* return number of characters immediately available */
218 l = msgbufp->msg_bufx - msgbufp->msg_bufr;
221 l += msgbufp->msg_size;
230 logsoftc.sc_state |= LOG_ASYNC;
232 logsoftc.sc_state &= ~LOG_ASYNC;
236 return (fsetown(*(int *)data, &logsoftc.sc_sigio));
239 *(int *)data = fgetown(&logsoftc.sc_sigio);
242 /* This is deprecated, FIOSETOWN should be used instead. */
244 return (fsetown(-(*(int *)data), &logsoftc.sc_sigio));
246 /* This is deprecated, FIOGETOWN should be used instead */
248 *(int *)data = -fgetown(&logsoftc.sc_sigio);
258 log_drvinit(void *unused)
261 make_dev(&log_cdevsw, 0, UID_ROOT, GID_WHEEL, 0600, "klog");
264 SYSINIT(logdev,SI_SUB_DRIVERS,SI_ORDER_MIDDLE+CDEV_MAJOR,log_drvinit,NULL)