subr_log.c revision 1.6
1230363Sdas/* $OpenBSD: subr_log.c,v 1.6 2000/02/22 19:28:03 deraadt Exp $ */ 2230363Sdas/* $NetBSD: subr_log.c,v 1.11 1996/03/30 22:24:44 christos Exp $ */ 3230363Sdas 4230363Sdas/* 5230363Sdas * Copyright (c) 1982, 1986, 1993 6230363Sdas * The Regents of the University of California. All rights reserved. 7230363Sdas * 8230363Sdas * Redistribution and use in source and binary forms, with or without 9230363Sdas * modification, are permitted provided that the following conditions 10230363Sdas * are met: 11230363Sdas * 1. Redistributions of source code must retain the above copyright 12230363Sdas * notice, this list of conditions and the following disclaimer. 13230363Sdas * 2. Redistributions in binary form must reproduce the above copyright 14230363Sdas * notice, this list of conditions and the following disclaimer in the 15230363Sdas * documentation and/or other materials provided with the distribution. 16230363Sdas * 3. All advertising materials mentioning features or use of this software 17230363Sdas * must display the following acknowledgement: 18230363Sdas * This product includes software developed by the University of 19230363Sdas * California, Berkeley and its contributors. 20230363Sdas * 4. Neither the name of the University nor the names of its contributors 21230363Sdas * may be used to endorse or promote products derived from this software 22230363Sdas * without specific prior written permission. 23230363Sdas * 24230363Sdas * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 25230363Sdas * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 26230363Sdas * 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 59struct 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 67int log_open; /* also used in log() */ 68int msgbufmapped; /* is the message buffer mapped */ 69int msgbufenabled; /* is logging to the buffer enabled */ 70struct msgbuf *msgbufp; /* the mapped buffer, itself. */ 71 72#define offsetof(type, member) ((size_t)(&((type *)0)->member)) 73 74void 75initmsgbuf(buf, bufsize) 76 caddr_t buf; 77 size_t bufsize; 78{ 79 register struct msgbuf *mbp; 80 long new_bufs; 81 82 /* Sanity-check the given size. */ 83 if (bufsize < sizeof(struct msgbuf)) 84 return; 85 86 mbp = msgbufp = (struct msgbuf *)buf; 87 88 new_bufs = bufsize - offsetof(struct msgbuf, msg_bufc); 89 if ((mbp->msg_magic != MSG_MAGIC) || (mbp->msg_bufs != new_bufs) || 90 (mbp->msg_bufr < 0) || (mbp->msg_bufr >= mbp->msg_bufs) || 91 (mbp->msg_bufx < 0) || (mbp->msg_bufx >= mbp->msg_bufs)) { 92 /* 93 * If the buffer magic number is wrong, has changed 94 * size (which shouldn't happen often), or is 95 * internally inconsistent, initialize it. 96 */ 97 98 bzero(buf, bufsize); 99 mbp->msg_magic = MSG_MAGIC; 100 mbp->msg_bufs = new_bufs; 101 } 102 103 /* mark it as ready for use. */ 104 msgbufmapped = msgbufenabled = 1; 105} 106 107/*ARGSUSED*/ 108int 109logopen(dev, flags, mode, p) 110 dev_t dev; 111 int flags, mode; 112 struct proc *p; 113{ 114 if (log_open) 115 return (EBUSY); 116 log_open = 1; 117 return (0); 118} 119 120/*ARGSUSED*/ 121int 122logclose(dev, flag, mode, p) 123 dev_t dev; 124 int flag, mode; 125 struct proc *p; 126{ 127 128 log_open = 0; 129 logsoftc.sc_state = 0; 130 return (0); 131} 132 133/*ARGSUSED*/ 134int 135logread(dev, uio, flag) 136 dev_t dev; 137 struct uio *uio; 138 int flag; 139{ 140 register struct msgbuf *mbp = msgbufp; 141 register long l; 142 register int s; 143 int error = 0; 144 145 s = splhigh(); 146 while (mbp->msg_bufr == mbp->msg_bufx) { 147 if (flag & IO_NDELAY) { 148 splx(s); 149 return (EWOULDBLOCK); 150 } 151 logsoftc.sc_state |= LOG_RDWAIT; 152 error = tsleep((caddr_t)mbp, LOG_RDPRI | PCATCH, 153 "klog", 0); 154 if (error) { 155 splx(s); 156 return (error); 157 } 158 } 159 splx(s); 160 logsoftc.sc_state &= ~LOG_RDWAIT; 161 162 while (uio->uio_resid > 0) { 163 l = mbp->msg_bufx - mbp->msg_bufr; 164 if (l < 0) 165 l = mbp->msg_bufs - mbp->msg_bufr; 166 l = min(l, uio->uio_resid); 167 if (l == 0) 168 break; 169 error = uiomove((caddr_t)&mbp->msg_bufc[mbp->msg_bufr], 170 (int)l, uio); 171 if (error) 172 break; 173 mbp->msg_bufr += l; 174 if (mbp->msg_bufr < 0 || mbp->msg_bufr >= mbp->msg_bufs) 175 mbp->msg_bufr = 0; 176 } 177 return (error); 178} 179 180/*ARGSUSED*/ 181int 182logselect(dev, rw, p) 183 dev_t dev; 184 int rw; 185 struct proc *p; 186{ 187 int s = splhigh(); 188 189 switch (rw) { 190 191 case FREAD: 192 if (msgbufp->msg_bufr != msgbufp->msg_bufx) { 193 splx(s); 194 return (1); 195 } 196 selrecord(p, &logsoftc.sc_selp); 197 break; 198 } 199 splx(s); 200 return (0); 201} 202 203void 204logwakeup() 205{ 206 if (!log_open) 207 return; 208 selwakeup(&logsoftc.sc_selp); 209 if (logsoftc.sc_state & LOG_ASYNC) 210 csignal(logsoftc.sc_pgid, SIGIO, 211 logsoftc.sc_siguid, logsoftc.sc_sigeuid); 212 if (logsoftc.sc_state & LOG_RDWAIT) { 213 wakeup((caddr_t)msgbufp); 214 logsoftc.sc_state &= ~LOG_RDWAIT; 215 } 216} 217 218/*ARGSUSED*/ 219int 220logioctl(dev, com, data, flag, p) 221 dev_t dev; 222 u_long com; 223 caddr_t data; 224 int flag; 225 struct proc *p; 226{ 227 long l; 228 int s; 229 230 switch (com) { 231 232 /* return number of characters immediately available */ 233 case FIONREAD: 234 s = splhigh(); 235 l = msgbufp->msg_bufx - msgbufp->msg_bufr; 236 splx(s); 237 if (l < 0) 238 l += msgbufp->msg_bufs; 239 *(int *)data = l; 240 break; 241 242 case FIONBIO: 243 break; 244 245 case FIOASYNC: 246 if (*(int *)data) 247 logsoftc.sc_state |= LOG_ASYNC; 248 else 249 logsoftc.sc_state &= ~LOG_ASYNC; 250 break; 251 252 case TIOCSPGRP: 253 logsoftc.sc_pgid = *(int *)data; 254 logsoftc.sc_siguid = p->p_cred->p_ruid; 255 logsoftc.sc_sigeuid = p->p_ucred->cr_uid; 256 break; 257 258 case TIOCGPGRP: 259 *(int *)data = logsoftc.sc_pgid; 260 break; 261 262 default: 263 return (-1); 264 } 265 return (0); 266} 267