| 1 | /* |
| 2 | * Copyright (c) 1982, 1986, 1993 |
| 3 | * The Regents of the University of California. All rights reserved. |
| 4 | * |
| 5 | * Redistribution and use in source and binary forms, with or without |
| 6 | * modification, are permitted provided that the following conditions |
| 7 | * are met: |
| 8 | * 1. Redistributions of source code must retain the above copyright |
| 9 | * notice, this list of conditions and the following disclaimer. |
| 10 | * 2. Redistributions in binary form must reproduce the above copyright |
| 11 | * notice, this list of conditions and the following disclaimer in the |
| 12 | * documentation and/or other materials provided with the distribution. |
| 13 | * 3. Neither the name of the University nor the names of its contributors |
| 14 | * may be used to endorse or promote products derived from this software |
| 15 | * without specific prior written permission. |
| 16 | * |
| 17 | * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND |
| 18 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
| 19 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
| 20 | * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE |
| 21 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
| 22 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
| 23 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
| 24 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
| 25 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
| 26 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
| 27 | * SUCH DAMAGE. |
| 28 | * |
| 29 | * @(#)subr_log.c 8.1 (Berkeley) 6/10/93 |
| 30 | * $FreeBSD: src/sys/kern/subr_log.c,v 1.39.2.2 2001/06/02 08:11:25 phk Exp $ |
| 31 | */ |
| 32 | |
| 33 | /* |
| 34 | * Error log buffer for kernel printf's. |
| 35 | */ |
| 36 | |
| 37 | #include <sys/param.h> |
| 38 | #include <sys/systm.h> |
| 39 | #include <sys/conf.h> |
| 40 | #include <sys/device.h> |
| 41 | #include <sys/proc.h> |
| 42 | #include <sys/vnode.h> |
| 43 | #include <sys/filio.h> |
| 44 | #include <sys/ttycom.h> |
| 45 | #include <sys/msgbuf.h> |
| 46 | #include <sys/signalvar.h> |
| 47 | #include <sys/kernel.h> |
| 48 | #include <sys/event.h> |
| 49 | #include <sys/filedesc.h> |
| 50 | #include <sys/sysctl.h> |
| 51 | #include <sys/thread2.h> |
| 52 | |
| 53 | #define LOG_ASYNC 0x04 |
| 54 | #define LOG_RDWAIT 0x08 |
| 55 | |
| 56 | static d_open_t logopen; |
| 57 | static d_close_t logclose; |
| 58 | static d_read_t logread; |
| 59 | static d_ioctl_t logioctl; |
| 60 | static d_kqfilter_t logkqfilter; |
| 61 | |
| 62 | static void logtimeout(void *arg); |
| 63 | static void logfiltdetach(struct knote *kn); |
| 64 | static int logfiltread(struct knote *kn, long hint); |
| 65 | |
| 66 | #define CDEV_MAJOR 7 |
| 67 | static struct dev_ops log_ops = { |
| 68 | { "log", 0, 0 }, |
| 69 | .d_open = logopen, |
| 70 | .d_close = logclose, |
| 71 | .d_read = logread, |
| 72 | .d_ioctl = logioctl, |
| 73 | .d_kqfilter = logkqfilter |
| 74 | }; |
| 75 | |
| 76 | static struct logsoftc { |
| 77 | int sc_state; /* see above for possibilities */ |
| 78 | struct kqinfo sc_kqp; /* processes waiting on I/O */ |
| 79 | struct sigio *sc_sigio; /* information for async I/O */ |
| 80 | struct callout sc_callout; /* callout to wakeup syslog */ |
| 81 | } logsoftc; |
| 82 | |
| 83 | int log_open; /* also used in log() */ |
| 84 | |
| 85 | /* Times per second to check for a pending syslog wakeup. */ |
| 86 | static int log_wakeups_per_second = 5; |
| 87 | SYSCTL_INT(_kern, OID_AUTO, log_wakeups_per_second, CTLFLAG_RW, |
| 88 | &log_wakeups_per_second, 0, ""); |
| 89 | |
| 90 | /*ARGSUSED*/ |
| 91 | static int |
| 92 | logopen(struct dev_open_args *ap) |
| 93 | { |
| 94 | struct proc *p = curproc; |
| 95 | |
| 96 | KKASSERT(p != NULL); |
| 97 | if (log_open) |
| 98 | return (EBUSY); |
| 99 | log_open = 1; |
| 100 | callout_init_mp(&logsoftc.sc_callout); |
| 101 | fsetown(p->p_pid, &logsoftc.sc_sigio); /* signal process only */ |
| 102 | callout_reset(&logsoftc.sc_callout, hz / log_wakeups_per_second, |
| 103 | logtimeout, NULL); |
| 104 | return (0); |
| 105 | } |
| 106 | |
| 107 | /*ARGSUSED*/ |
| 108 | static int |
| 109 | logclose(struct dev_close_args *ap) |
| 110 | { |
| 111 | log_open = 0; |
| 112 | callout_stop(&logsoftc.sc_callout); |
| 113 | logsoftc.sc_state = 0; |
| 114 | funsetown(&logsoftc.sc_sigio); |
| 115 | return (0); |
| 116 | } |
| 117 | |
| 118 | /*ARGSUSED*/ |
| 119 | static int |
| 120 | logread(struct dev_read_args *ap) |
| 121 | { |
| 122 | struct uio *uio = ap->a_uio; |
| 123 | struct msgbuf *mbp = msgbufp; |
| 124 | long l; |
| 125 | int error = 0; |
| 126 | |
| 127 | crit_enter(); |
| 128 | while (mbp->msg_bufr == mbp->msg_bufx) { |
| 129 | if (ap->a_ioflag & IO_NDELAY) { |
| 130 | crit_exit(); |
| 131 | return (EWOULDBLOCK); |
| 132 | } |
| 133 | logsoftc.sc_state |= LOG_RDWAIT; |
| 134 | if ((error = tsleep((caddr_t)mbp, PCATCH, "klog", 0))) { |
| 135 | crit_exit(); |
| 136 | return (error); |
| 137 | } |
| 138 | } |
| 139 | crit_exit(); |
| 140 | logsoftc.sc_state &= ~LOG_RDWAIT; |
| 141 | |
| 142 | while (uio->uio_resid > 0) { |
| 143 | l = (long)mbp->msg_bufx - (long)mbp->msg_bufr; |
| 144 | if (l < 0) |
| 145 | l = mbp->msg_size - mbp->msg_bufr; |
| 146 | l = (long)szmin(l, uio->uio_resid); |
| 147 | if (l == 0) |
| 148 | break; |
| 149 | error = uiomove((caddr_t)msgbufp->msg_ptr + mbp->msg_bufr, |
| 150 | (size_t)l, uio); |
| 151 | if (error) |
| 152 | break; |
| 153 | mbp->msg_bufr += l; |
| 154 | if (mbp->msg_bufr >= mbp->msg_size) |
| 155 | mbp->msg_bufr = 0; |
| 156 | } |
| 157 | return (error); |
| 158 | } |
| 159 | |
| 160 | static struct filterops logread_filtops = |
| 161 | { FILTEROP_ISFD, NULL, logfiltdetach, logfiltread }; |
| 162 | |
| 163 | static int |
| 164 | logkqfilter(struct dev_kqfilter_args *ap) |
| 165 | { |
| 166 | struct knote *kn = ap->a_kn; |
| 167 | struct klist *klist = &logsoftc.sc_kqp.ki_note; |
| 168 | |
| 169 | ap->a_result = 0; |
| 170 | switch (kn->kn_filter) { |
| 171 | case EVFILT_READ: |
| 172 | kn->kn_fop = &logread_filtops; |
| 173 | break; |
| 174 | default: |
| 175 | ap->a_result = EOPNOTSUPP; |
| 176 | return (0); |
| 177 | } |
| 178 | |
| 179 | knote_insert(klist, kn); |
| 180 | |
| 181 | return (0); |
| 182 | } |
| 183 | |
| 184 | static void |
| 185 | logfiltdetach(struct knote *kn) |
| 186 | { |
| 187 | struct klist *klist = &logsoftc.sc_kqp.ki_note; |
| 188 | |
| 189 | knote_remove(klist, kn); |
| 190 | } |
| 191 | |
| 192 | static int |
| 193 | logfiltread(struct knote *kn, long hint) |
| 194 | { |
| 195 | int ret = 0; |
| 196 | |
| 197 | crit_enter(); |
| 198 | if (msgbufp->msg_bufr != msgbufp->msg_bufx) |
| 199 | ret = 1; |
| 200 | crit_exit(); |
| 201 | |
| 202 | return (ret); |
| 203 | } |
| 204 | |
| 205 | static void |
| 206 | logtimeout(void *arg) |
| 207 | { |
| 208 | if (!log_open) |
| 209 | return; |
| 210 | if (msgbuftrigger == 0) { |
| 211 | callout_reset(&logsoftc.sc_callout, |
| 212 | hz / log_wakeups_per_second, logtimeout, NULL); |
| 213 | return; |
| 214 | } |
| 215 | msgbuftrigger = 0; |
| 216 | KNOTE(&logsoftc.sc_kqp.ki_note, 0); |
| 217 | if ((logsoftc.sc_state & LOG_ASYNC) && logsoftc.sc_sigio != NULL) |
| 218 | pgsigio(logsoftc.sc_sigio, SIGIO, 0); |
| 219 | if (logsoftc.sc_state & LOG_RDWAIT) { |
| 220 | wakeup((caddr_t)msgbufp); |
| 221 | logsoftc.sc_state &= ~LOG_RDWAIT; |
| 222 | } |
| 223 | callout_reset(&logsoftc.sc_callout, hz / log_wakeups_per_second, |
| 224 | logtimeout, NULL); |
| 225 | } |
| 226 | |
| 227 | /*ARGSUSED*/ |
| 228 | static int |
| 229 | logioctl(struct dev_ioctl_args *ap) |
| 230 | { |
| 231 | long l; |
| 232 | |
| 233 | switch (ap->a_cmd) { |
| 234 | case FIONREAD: |
| 235 | /* return number of characters immediately available */ |
| 236 | crit_enter(); |
| 237 | l = msgbufp->msg_bufx - msgbufp->msg_bufr; |
| 238 | crit_exit(); |
| 239 | if (l < 0) |
| 240 | l += msgbufp->msg_size; |
| 241 | *(int *)ap->a_data = l; |
| 242 | break; |
| 243 | |
| 244 | case FIOASYNC: |
| 245 | if (*(int *)ap->a_data) |
| 246 | logsoftc.sc_state |= LOG_ASYNC; |
| 247 | else |
| 248 | logsoftc.sc_state &= ~LOG_ASYNC; |
| 249 | break; |
| 250 | |
| 251 | case FIOSETOWN: |
| 252 | return (fsetown(*(int *)ap->a_data, &logsoftc.sc_sigio)); |
| 253 | |
| 254 | case FIOGETOWN: |
| 255 | *(int *)ap->a_data = fgetown(&logsoftc.sc_sigio); |
| 256 | break; |
| 257 | |
| 258 | /* This is deprecated, FIOSETOWN should be used instead. */ |
| 259 | case TIOCSPGRP: |
| 260 | return (fsetown(-(*(int *)ap->a_data), &logsoftc.sc_sigio)); |
| 261 | |
| 262 | /* This is deprecated, FIOGETOWN should be used instead */ |
| 263 | case TIOCGPGRP: |
| 264 | *(int *)ap->a_data = -fgetown(&logsoftc.sc_sigio); |
| 265 | break; |
| 266 | |
| 267 | default: |
| 268 | return (ENOTTY); |
| 269 | } |
| 270 | return (0); |
| 271 | } |
| 272 | |
| 273 | static void |
| 274 | log_drvinit(void *unused) |
| 275 | { |
| 276 | make_dev(&log_ops, 0, UID_ROOT, GID_WHEEL, 0600, "klog"); |
| 277 | } |
| 278 | |
| 279 | SYSINIT(logdev,SI_SUB_DRIVERS,SI_ORDER_MIDDLE+CDEV_MAJOR,log_drvinit,NULL) |