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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>
54 #define LOG_RDPRI (PZERO + 1)
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;
66 static struct cdevsw log_cdevsw = {
74 /* strategy */ nostrategy,
83 static struct logsoftc {
84 int sc_state; /* see above for possibilities */
85 struct selinfo sc_selp; /* process waiting on select call */
86 struct sigio *sc_sigio; /* information for async I/O */
89 int log_open; /* also used in log() */
93 logopen(dev, flags, mode, p)
101 fsetown(p->p_pid, &logsoftc.sc_sigio); /* signal process only */
107 logclose(dev, flag, mode, p)
114 logsoftc.sc_state = 0;
115 funsetown(logsoftc.sc_sigio);
121 logread(dev, uio, flag)
126 register struct msgbuf *mbp = msgbufp;
132 while (mbp->msg_bufr == mbp->msg_bufx) {
133 if (flag & IO_NDELAY) {
135 return (EWOULDBLOCK);
137 logsoftc.sc_state |= LOG_RDWAIT;
138 if ((error = tsleep((caddr_t)mbp, LOG_RDPRI | PCATCH,
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 = min(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, events, p)
177 if (events & (POLLIN | POLLRDNORM)) {
178 if (msgbufp->msg_bufr != msgbufp->msg_bufx)
179 revents |= events & (POLLIN | POLLRDNORM);
181 selrecord(p, &logsoftc.sc_selp);
192 selwakeup(&logsoftc.sc_selp);
193 if ((logsoftc.sc_state & LOG_ASYNC) && logsoftc.sc_sigio != NULL)
194 pgsigio(logsoftc.sc_sigio, SIGIO, 0);
195 if (logsoftc.sc_state & LOG_RDWAIT) {
196 wakeup((caddr_t)msgbufp);
197 logsoftc.sc_state &= ~LOG_RDWAIT;
203 logioctl(dev, com, data, flag, p)
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 static void log_drvinit __P((void *unused));
264 make_dev(&log_cdevsw, 0, UID_ROOT, GID_WHEEL, 0600, "klog");
267 SYSINIT(logdev,SI_SUB_DRIVERS,SI_ORDER_MIDDLE+CDEV_MAJOR,log_drvinit,NULL)