1 /* $OpenBSD: subr_log.c,v 1.5 1997/09/18 13:23:26 deraadt 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 69 /*ARGSUSED*/ 70 int 71 logopen(dev, flags, mode, p) 72 dev_t dev; 73 int flags, mode; 74 struct proc *p; 75 { 76 register struct msgbuf *mbp = msgbufp; 77 78 if (log_open) 79 return (EBUSY); 80 log_open = 1; 81 /* 82 * Potential race here with putchar() but since putchar should be 83 * called by autoconf, msg_magic should be initialized by the time 84 * we get here. 85 */ 86 if (mbp->msg_magic != MSG_MAGIC) { 87 register int i; 88 89 mbp->msg_magic = MSG_MAGIC; 90 mbp->msg_bufx = mbp->msg_bufr = 0; 91 for (i=0; i < MSG_BSIZE; i++) 92 mbp->msg_bufc[i] = 0; 93 } 94 return (0); 95 } 96 97 /*ARGSUSED*/ 98 int 99 logclose(dev, flag, mode, p) 100 dev_t dev; 101 int flag, mode; 102 struct proc *p; 103 { 104 105 log_open = 0; 106 logsoftc.sc_state = 0; 107 return (0); 108 } 109 110 /*ARGSUSED*/ 111 int 112 logread(dev, uio, flag) 113 dev_t dev; 114 struct uio *uio; 115 int flag; 116 { 117 register struct msgbuf *mbp = msgbufp; 118 register long l; 119 register int s; 120 int error = 0; 121 122 s = splhigh(); 123 while (mbp->msg_bufr == mbp->msg_bufx) { 124 if (flag & IO_NDELAY) { 125 splx(s); 126 return (EWOULDBLOCK); 127 } 128 logsoftc.sc_state |= LOG_RDWAIT; 129 error = tsleep((caddr_t)mbp, LOG_RDPRI | PCATCH, 130 "klog", 0); 131 if (error) { 132 splx(s); 133 return (error); 134 } 135 } 136 splx(s); 137 logsoftc.sc_state &= ~LOG_RDWAIT; 138 139 while (uio->uio_resid > 0) { 140 l = mbp->msg_bufx - mbp->msg_bufr; 141 if (l < 0) 142 l = MSG_BSIZE - mbp->msg_bufr; 143 l = min(l, uio->uio_resid); 144 if (l == 0) 145 break; 146 error = uiomove((caddr_t)&mbp->msg_bufc[mbp->msg_bufr], 147 (int)l, uio); 148 if (error) 149 break; 150 mbp->msg_bufr += l; 151 if (mbp->msg_bufr < 0 || mbp->msg_bufr >= MSG_BSIZE) 152 mbp->msg_bufr = 0; 153 } 154 return (error); 155 } 156 157 /*ARGSUSED*/ 158 int 159 logselect(dev, rw, p) 160 dev_t dev; 161 int rw; 162 struct proc *p; 163 { 164 int s = splhigh(); 165 166 switch (rw) { 167 168 case FREAD: 169 if (msgbufp->msg_bufr != msgbufp->msg_bufx) { 170 splx(s); 171 return (1); 172 } 173 selrecord(p, &logsoftc.sc_selp); 174 break; 175 } 176 splx(s); 177 return (0); 178 } 179 180 void 181 logwakeup() 182 { 183 if (!log_open) 184 return; 185 selwakeup(&logsoftc.sc_selp); 186 if (logsoftc.sc_state & LOG_ASYNC) 187 csignal(logsoftc.sc_pgid, SIGIO, 188 logsoftc.sc_siguid, logsoftc.sc_sigeuid); 189 if (logsoftc.sc_state & LOG_RDWAIT) { 190 wakeup((caddr_t)msgbufp); 191 logsoftc.sc_state &= ~LOG_RDWAIT; 192 } 193 } 194 195 /*ARGSUSED*/ 196 int 197 logioctl(dev, com, data, flag, p) 198 dev_t dev; 199 u_long com; 200 caddr_t data; 201 int flag; 202 struct proc *p; 203 { 204 long l; 205 int s; 206 207 switch (com) { 208 209 /* return number of characters immediately available */ 210 case FIONREAD: 211 s = splhigh(); 212 l = msgbufp->msg_bufx - msgbufp->msg_bufr; 213 splx(s); 214 if (l < 0) 215 l += MSG_BSIZE; 216 *(int *)data = l; 217 break; 218 219 case FIONBIO: 220 break; 221 222 case FIOASYNC: 223 if (*(int *)data) 224 logsoftc.sc_state |= LOG_ASYNC; 225 else 226 logsoftc.sc_state &= ~LOG_ASYNC; 227 break; 228 229 case TIOCSPGRP: 230 logsoftc.sc_pgid = *(int *)data; 231 logsoftc.sc_siguid = p->p_cred->p_ruid; 232 logsoftc.sc_sigeuid = p->p_ucred->cr_uid; 233 break; 234 235 case TIOCGPGRP: 236 *(int *)data = logsoftc.sc_pgid; 237 break; 238 239 default: 240 return (-1); 241 } 242 return (0); 243 } 244