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29 * @(#)subr_log.c 8.1 (Berkeley) 6/10/93
33 * Error log buffer for kernel printf's.
36 #include <sys/cdefs.h>
37 __FBSDID("$FreeBSD$");
39 #include <sys/param.h>
40 #include <sys/systm.h>
43 #include <sys/vnode.h>
44 #include <sys/filio.h>
45 #include <sys/ttycom.h>
46 #include <sys/msgbuf.h>
47 #include <sys/signalvar.h>
48 #include <sys/kernel.h>
50 #include <sys/filedesc.h>
51 #include <sys/sysctl.h>
53 #define LOG_RDPRI (PZERO + 1)
55 #define LOG_ASYNC 0x04
56 #define LOG_RDWAIT 0x08
58 static d_open_t logopen;
59 static d_close_t logclose;
60 static d_read_t logread;
61 static d_ioctl_t logioctl;
62 static d_poll_t logpoll;
64 static void logtimeout(void *arg);
66 static struct cdevsw log_cdevsw = {
67 .d_version = D_VERSION,
68 .d_flags = D_NEEDGIANT,
77 static struct logsoftc {
78 int sc_state; /* see above for possibilities */
79 struct selinfo sc_selp; /* process waiting on select call */
80 struct sigio *sc_sigio; /* information for async I/O */
81 struct callout sc_callout; /* callout to wakeup syslog */
84 int log_open; /* also used in log() */
86 /* Times per second to check for a pending syslog wakeup. */
87 static int log_wakeups_per_second = 5;
88 SYSCTL_INT(_kern, OID_AUTO, log_wakeups_per_second, CTLFLAG_RW,
89 &log_wakeups_per_second, 0, "");
93 logopen(struct cdev *dev, int flags, int mode, struct thread *td)
98 callout_init(&logsoftc.sc_callout, 0);
99 fsetown(td->td_proc->p_pid, &logsoftc.sc_sigio); /* signal process only */
100 if (log_wakeups_per_second < 1) {
101 printf("syslog wakeup is less than one. Adjusting to 1.\n");
102 log_wakeups_per_second = 1;
104 callout_reset(&logsoftc.sc_callout, hz / log_wakeups_per_second,
111 logclose(struct cdev *dev, int flag, int mode, struct thread *td)
115 callout_stop(&logsoftc.sc_callout);
116 logsoftc.sc_state = 0;
117 funsetown(&logsoftc.sc_sigio);
123 logread(struct cdev *dev, struct uio *uio, int flag)
126 struct msgbuf *mbp = msgbufp;
130 while (msgbuf_getcount(mbp) == 0) {
131 if (flag & IO_NDELAY) {
133 return (EWOULDBLOCK);
135 logsoftc.sc_state |= LOG_RDWAIT;
136 if ((error = tsleep(mbp, LOG_RDPRI | PCATCH, "klog", 0))) {
142 logsoftc.sc_state &= ~LOG_RDWAIT;
144 while (uio->uio_resid > 0) {
145 l = imin(sizeof(buf), uio->uio_resid);
146 l = msgbuf_getbytes(mbp, buf, l);
149 error = uiomove(buf, l, uio);
158 logpoll(struct cdev *dev, int events, struct thread *td)
165 if (events & (POLLIN | POLLRDNORM)) {
166 if (msgbuf_getcount(msgbufp) > 0)
167 revents |= events & (POLLIN | POLLRDNORM);
169 selrecord(td, &logsoftc.sc_selp);
176 logtimeout(void *arg)
181 if (log_wakeups_per_second < 1) {
182 printf("syslog wakeup is less than one. Adjusting to 1.\n");
183 log_wakeups_per_second = 1;
185 if (msgbuftrigger == 0) {
186 callout_reset(&logsoftc.sc_callout,
187 hz / log_wakeups_per_second, logtimeout, NULL);
191 selwakeuppri(&logsoftc.sc_selp, LOG_RDPRI);
192 if ((logsoftc.sc_state & LOG_ASYNC) && logsoftc.sc_sigio != NULL)
193 pgsigio(&logsoftc.sc_sigio, SIGIO, 0);
194 if (logsoftc.sc_state & LOG_RDWAIT) {
196 logsoftc.sc_state &= ~LOG_RDWAIT;
198 callout_reset(&logsoftc.sc_callout, hz / log_wakeups_per_second,
204 logioctl(struct cdev *dev, u_long com, caddr_t data, int flag, struct thread *td)
209 /* return number of characters immediately available */
211 *(int *)data = msgbuf_getcount(msgbufp);
219 logsoftc.sc_state |= LOG_ASYNC;
221 logsoftc.sc_state &= ~LOG_ASYNC;
225 return (fsetown(*(int *)data, &logsoftc.sc_sigio));
228 *(int *)data = fgetown(&logsoftc.sc_sigio);
231 /* This is deprecated, FIOSETOWN should be used instead. */
233 return (fsetown(-(*(int *)data), &logsoftc.sc_sigio));
235 /* This is deprecated, FIOGETOWN should be used instead */
237 *(int *)data = -fgetown(&logsoftc.sc_sigio);
247 log_drvinit(void *unused)
250 make_dev(&log_cdevsw, 0, UID_ROOT, GID_WHEEL, 0600, "klog");
253 SYSINIT(logdev,SI_SUB_DRIVERS,SI_ORDER_MIDDLE,log_drvinit,NULL);