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. All advertising materials mentioning features or use of this software 14 * must display the following acknowledgement: 15 * This product includes software developed by the University of 16 * California, Berkeley and its contributors. 17 * 4. Neither the name of the University nor the names of its contributors 18 * may be used to endorse or promote products derived from this software 19 * without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 * 33 * @(#)subr_log.c 8.1 (Berkeley) 6/10/93 34 * $Id$ 35 */ 36 37 /* 38 * Error log buffer for kernel printf's. 39 */ 40 41 #include <sys/param.h> 42 #include <sys/systm.h> 43 #include <sys/conf.h> 44 #include <sys/proc.h> 45 #include <sys/vnode.h> 46 #include <sys/ioctl.h> 47 #include <sys/msgbuf.h> 48 #include <sys/file.h> 49 #include <sys/signalvar.h> 50 #include <sys/kernel.h> 51 #ifdef DEVFS 52 #include <sys/devfsext.h> 53 #endif /*DEVFS*/ 54 55 #define LOG_RDPRI (PZERO + 1) 56 57 #define LOG_ASYNC 0x04 58 #define LOG_RDWAIT 0x08 59 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_select_t logselect; 65 66 #define CDEV_MAJOR 7 67 static struct cdevsw log_cdevsw = 68 { logopen, logclose, logread, nowrite, /*7*/ 69 logioctl, nostop, nullreset, nodevtotty,/* klog */ 70 logselect, nommap, NULL, "log", NULL, -1 }; 71 72 static struct logsoftc { 73 int sc_state; /* see above for possibilities */ 74 struct selinfo sc_selp; /* process waiting on select call */ 75 int sc_pgid; /* process/group for async I/O */ 76 } logsoftc; 77 78 int log_open; /* also used in log() */ 79 80 /*ARGSUSED*/ 81 static int 82 logopen(dev, flags, mode, p) 83 dev_t dev; 84 int flags, mode; 85 struct proc *p; 86 { 87 if (log_open) 88 return (EBUSY); 89 log_open = 1; 90 logsoftc.sc_pgid = p->p_pid; /* signal process only */ 91 return (0); 92 } 93 94 /*ARGSUSED*/ 95 static int 96 logclose(dev, flag, mode, p) 97 dev_t dev; 98 int flag, mode; 99 struct proc *p; 100 { 101 102 log_open = 0; 103 logsoftc.sc_state = 0; 104 return (0); 105 } 106 107 /*ARGSUSED*/ 108 static int 109 logread(dev, uio, flag) 110 dev_t dev; 111 struct uio *uio; 112 int flag; 113 { 114 register struct msgbuf *mbp = msgbufp; 115 register long l; 116 register int s; 117 int error = 0; 118 119 s = splhigh(); 120 while (mbp->msg_bufr == mbp->msg_bufx) { 121 if (flag & IO_NDELAY) { 122 splx(s); 123 return (EWOULDBLOCK); 124 } 125 logsoftc.sc_state |= LOG_RDWAIT; 126 if ((error = tsleep((caddr_t)mbp, LOG_RDPRI | PCATCH, 127 "klog", 0))) { 128 splx(s); 129 return (error); 130 } 131 } 132 splx(s); 133 logsoftc.sc_state &= ~LOG_RDWAIT; 134 135 while (uio->uio_resid > 0) { 136 l = mbp->msg_bufx - mbp->msg_bufr; 137 if (l < 0) 138 l = MSG_BSIZE - mbp->msg_bufr; 139 l = min(l, uio->uio_resid); 140 if (l == 0) 141 break; 142 error = uiomove((caddr_t)&mbp->msg_bufc[mbp->msg_bufr], 143 (int)l, uio); 144 if (error) 145 break; 146 mbp->msg_bufr += l; 147 if (mbp->msg_bufr >= MSG_BSIZE) 148 mbp->msg_bufr = 0; 149 } 150 return (error); 151 } 152 153 /*ARGSUSED*/ 154 static int 155 logselect(dev, rw, p) 156 dev_t dev; 157 int rw; 158 struct proc *p; 159 { 160 int s = splhigh(); 161 162 switch (rw) { 163 164 case FREAD: 165 if (msgbufp->msg_bufr != msgbufp->msg_bufx) { 166 splx(s); 167 return (1); 168 } 169 selrecord(p, &logsoftc.sc_selp); 170 break; 171 } 172 splx(s); 173 return (0); 174 } 175 176 void 177 logwakeup() 178 { 179 struct proc *p; 180 181 if (!log_open) 182 return; 183 selwakeup(&logsoftc.sc_selp); 184 if (logsoftc.sc_state & LOG_ASYNC) { 185 if (logsoftc.sc_pgid < 0) 186 gsignal(-logsoftc.sc_pgid, SIGIO); 187 else if ((p = pfind(logsoftc.sc_pgid))) 188 psignal(p, SIGIO); 189 } 190 if (logsoftc.sc_state & LOG_RDWAIT) { 191 wakeup((caddr_t)msgbufp); 192 logsoftc.sc_state &= ~LOG_RDWAIT; 193 } 194 } 195 196 /*ARGSUSED*/ 197 static int 198 logioctl(dev, com, data, flag, p) 199 dev_t dev; 200 int com; 201 caddr_t data; 202 int flag; 203 struct proc *p; 204 { 205 long l; 206 int s; 207 208 switch (com) { 209 210 /* return number of characters immediately available */ 211 case FIONREAD: 212 s = splhigh(); 213 l = msgbufp->msg_bufx - msgbufp->msg_bufr; 214 splx(s); 215 if (l < 0) 216 l += MSG_BSIZE; 217 *(int *)data = l; 218 break; 219 220 case FIONBIO: 221 break; 222 223 case FIOASYNC: 224 if (*(int *)data) 225 logsoftc.sc_state |= LOG_ASYNC; 226 else 227 logsoftc.sc_state &= ~LOG_ASYNC; 228 break; 229 230 case TIOCSPGRP: 231 logsoftc.sc_pgid = *(int *)data; 232 break; 233 234 case TIOCGPGRP: 235 *(int *)data = logsoftc.sc_pgid; 236 break; 237 238 default: 239 return (ENOTTY); 240 } 241 return (0); 242 } 243 244 static log_devsw_installed = 0; 245 #ifdef DEVFS 246 static void *log_devfs_token; 247 #endif 248 249 static void 250 log_drvinit(void *unused) 251 { 252 dev_t dev; 253 254 if( ! log_devsw_installed ) { 255 dev = makedev(CDEV_MAJOR,0); 256 cdevsw_add(&dev,&log_cdevsw,NULL); 257 log_devsw_installed = 1; 258 #ifdef DEVFS 259 log_devfs_token = devfs_add_devswf(&log_cdevsw, 0, DV_CHR, 260 UID_ROOT, GID_WHEEL, 0600, 261 "klog"); 262 #endif 263 } 264 } 265 266 SYSINIT(logdev,SI_SUB_DRIVERS,SI_ORDER_MIDDLE+CDEV_MAJOR,log_drvinit,NULL) 267 268 269