1 /* $OpenBSD: subr_log.c,v 1.7 2001/04/06 04:42:07 csapuntz Exp $ */ 2 /* $NetBSD: subr_log.c,v 1.11 1996/03/30 22:24:44 christos Exp $ */ 3 4 /* 5 * Copyright (c) 1982, 1986, 1993 6 * The Regents of the University of California. All rights reserved. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 3. All advertising materials mentioning features or use of this software 17 * must display the following acknowledgement: 18 * This product includes software developed by the University of 19 * California, Berkeley and its contributors. 20 * 4. Neither the name of the University nor the names of its contributors 21 * may be used to endorse or promote products derived from this software 22 * without specific prior written permission. 23 * 24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 34 * SUCH DAMAGE. 35 * 36 * @(#)subr_log.c 8.1 (Berkeley) 6/10/93 37 */ 38 39 /* 40 * Error log buffer for kernel printf's. 41 */ 42 43 #include <sys/param.h> 44 #include <sys/systm.h> 45 #include <sys/proc.h> 46 #include <sys/vnode.h> 47 #include <sys/ioctl.h> 48 #include <sys/msgbuf.h> 49 #include <sys/file.h> 50 #include <sys/signalvar.h> 51 #include <sys/syslog.h> 52 #include <sys/conf.h> 53 54 #define LOG_RDPRI (PZERO + 1) 55 56 #define LOG_ASYNC 0x04 57 #define LOG_RDWAIT 0x08 58 59 struct logsoftc { 60 int sc_state; /* see above for possibilities */ 61 struct selinfo sc_selp; /* process waiting on select call */ 62 int sc_pgid; /* process/group for async I/O */ 63 uid_t sc_siguid; /* uid for process that set sc_pgid */ 64 uid_t sc_sigeuid; /* euid for process that set sc_pgid */ 65 } logsoftc; 66 67 int log_open; /* also used in log() */ 68 int msgbufmapped; /* is the message buffer mapped */ 69 int msgbufenabled; /* is logging to the buffer enabled */ 70 struct msgbuf *msgbufp; /* the mapped buffer, itself. */ 71 72 void 73 initmsgbuf(buf, bufsize) 74 caddr_t buf; 75 size_t bufsize; 76 { 77 register struct msgbuf *mbp; 78 long new_bufs; 79 80 /* Sanity-check the given size. */ 81 if (bufsize < sizeof(struct msgbuf)) 82 return; 83 84 mbp = msgbufp = (struct msgbuf *)buf; 85 86 new_bufs = bufsize - offsetof(struct msgbuf, msg_bufc); 87 if ((mbp->msg_magic != MSG_MAGIC) || (mbp->msg_bufs != new_bufs) || 88 (mbp->msg_bufr < 0) || (mbp->msg_bufr >= mbp->msg_bufs) || 89 (mbp->msg_bufx < 0) || (mbp->msg_bufx >= mbp->msg_bufs)) { 90 /* 91 * If the buffer magic number is wrong, has changed 92 * size (which shouldn't happen often), or is 93 * internally inconsistent, initialize it. 94 */ 95 96 bzero(buf, bufsize); 97 mbp->msg_magic = MSG_MAGIC; 98 mbp->msg_bufs = new_bufs; 99 } 100 101 /* mark it as ready for use. */ 102 msgbufmapped = msgbufenabled = 1; 103 } 104 105 /*ARGSUSED*/ 106 int 107 logopen(dev, flags, mode, p) 108 dev_t dev; 109 int flags, mode; 110 struct proc *p; 111 { 112 if (log_open) 113 return (EBUSY); 114 log_open = 1; 115 return (0); 116 } 117 118 /*ARGSUSED*/ 119 int 120 logclose(dev, flag, mode, p) 121 dev_t dev; 122 int flag, mode; 123 struct proc *p; 124 { 125 126 log_open = 0; 127 logsoftc.sc_state = 0; 128 return (0); 129 } 130 131 /*ARGSUSED*/ 132 int 133 logread(dev, uio, flag) 134 dev_t dev; 135 struct uio *uio; 136 int flag; 137 { 138 register struct msgbuf *mbp = msgbufp; 139 register long l; 140 register int s; 141 int error = 0; 142 143 s = splhigh(); 144 while (mbp->msg_bufr == mbp->msg_bufx) { 145 if (flag & IO_NDELAY) { 146 splx(s); 147 return (EWOULDBLOCK); 148 } 149 logsoftc.sc_state |= LOG_RDWAIT; 150 error = tsleep((caddr_t)mbp, LOG_RDPRI | PCATCH, 151 "klog", 0); 152 if (error) { 153 splx(s); 154 return (error); 155 } 156 } 157 splx(s); 158 logsoftc.sc_state &= ~LOG_RDWAIT; 159 160 while (uio->uio_resid > 0) { 161 l = mbp->msg_bufx - mbp->msg_bufr; 162 if (l < 0) 163 l = mbp->msg_bufs - mbp->msg_bufr; 164 l = min(l, uio->uio_resid); 165 if (l == 0) 166 break; 167 error = uiomove((caddr_t)&mbp->msg_bufc[mbp->msg_bufr], 168 (int)l, uio); 169 if (error) 170 break; 171 mbp->msg_bufr += l; 172 if (mbp->msg_bufr < 0 || mbp->msg_bufr >= mbp->msg_bufs) 173 mbp->msg_bufr = 0; 174 } 175 return (error); 176 } 177 178 /*ARGSUSED*/ 179 int 180 logselect(dev, rw, p) 181 dev_t dev; 182 int rw; 183 struct proc *p; 184 { 185 int s = splhigh(); 186 187 switch (rw) { 188 189 case FREAD: 190 if (msgbufp->msg_bufr != msgbufp->msg_bufx) { 191 splx(s); 192 return (1); 193 } 194 selrecord(p, &logsoftc.sc_selp); 195 break; 196 } 197 splx(s); 198 return (0); 199 } 200 201 void 202 logwakeup() 203 { 204 if (!log_open) 205 return; 206 selwakeup(&logsoftc.sc_selp); 207 if (logsoftc.sc_state & LOG_ASYNC) 208 csignal(logsoftc.sc_pgid, SIGIO, 209 logsoftc.sc_siguid, logsoftc.sc_sigeuid); 210 if (logsoftc.sc_state & LOG_RDWAIT) { 211 wakeup((caddr_t)msgbufp); 212 logsoftc.sc_state &= ~LOG_RDWAIT; 213 } 214 } 215 216 /*ARGSUSED*/ 217 int 218 logioctl(dev, com, data, flag, p) 219 dev_t dev; 220 u_long com; 221 caddr_t data; 222 int flag; 223 struct proc *p; 224 { 225 long l; 226 int s; 227 228 switch (com) { 229 230 /* return number of characters immediately available */ 231 case FIONREAD: 232 s = splhigh(); 233 l = msgbufp->msg_bufx - msgbufp->msg_bufr; 234 splx(s); 235 if (l < 0) 236 l += msgbufp->msg_bufs; 237 *(int *)data = l; 238 break; 239 240 case FIONBIO: 241 break; 242 243 case FIOASYNC: 244 if (*(int *)data) 245 logsoftc.sc_state |= LOG_ASYNC; 246 else 247 logsoftc.sc_state &= ~LOG_ASYNC; 248 break; 249 250 case TIOCSPGRP: 251 logsoftc.sc_pgid = *(int *)data; 252 logsoftc.sc_siguid = p->p_cred->p_ruid; 253 logsoftc.sc_sigeuid = p->p_ucred->cr_uid; 254 break; 255 256 case TIOCGPGRP: 257 *(int *)data = logsoftc.sc_pgid; 258 break; 259 260 default: 261 return (-1); 262 } 263 return (0); 264 } 265