1 /* 2 * Copyright (c) 1982 Regents of the University of California. 3 * All rights reserved. The Berkeley software License Agreement 4 * specifies the terms and conditions for redistribution. 5 * 6 * @(#)subr_log.c 6.5 (Berkeley) 06/08/85 7 */ 8 9 /* 10 * Error log buffer for kernel printf's. 11 */ 12 13 #include "param.h" 14 #include "dir.h" 15 #include "user.h" 16 #include "proc.h" 17 #include "ioctl.h" 18 #include "msgbuf.h" 19 #include "file.h" 20 #include "errno.h" 21 22 #define LOG_RDPRI (PZERO + 1) 23 24 #define LOG_NBIO 0x02 25 #define LOG_ASYNC 0x04 26 #define LOG_RDWAIT 0x08 27 28 struct logsoftc { 29 int sc_state; /* see above for possibilities */ 30 struct proc *sc_selp; /* process waiting on select call */ 31 int sc_pgrp; /* process group for async I/O */ 32 } logsoftc; 33 34 int log_open; /* also used in log() */ 35 36 #ifdef LOGDEBUG 37 /*VARARGS1*/ 38 xprintf(fmt, x1) 39 char *fmt; 40 unsigned x1; 41 { 42 43 prf(fmt, &x1, 1, (struct tty *)0); 44 } 45 #endif 46 47 logopen(dev) 48 dev_t dev; 49 { 50 51 #ifdef LOGDEBUG 52 xprintf("logopen: dev=0x%x\n", dev); 53 #endif 54 if (log_open) 55 return (EBUSY); 56 log_open = 1; 57 logsoftc.sc_selp = 0; 58 logsoftc.sc_pgrp = u.u_procp->p_pgrp; 59 /* 60 * Potential race here with putchar() but since putchar should be 61 * called by autoconf, msg_magic should be initialized by the time 62 * we get here. 63 */ 64 if (msgbuf.msg_magic != MSG_MAGIC) { 65 register int i; 66 67 msgbuf.msg_magic = MSG_MAGIC; 68 msgbuf.msg_bufx = msgbuf.msg_bufr = 0; 69 for (i=0; i < MSG_BSIZE; i++) 70 msgbuf.msg_bufc[i] = 0; 71 } 72 #ifdef LOGDEBUG 73 xprintf("logopen: bufx=%d, bufr=%d\n", msgbuf.msg_bufx, msgbuf.msg_bufr); 74 #endif 75 return (0); 76 } 77 78 logclose(dev, flag) 79 dev_t dev; 80 { 81 log_open = 0; 82 logsoftc.sc_state = 0; 83 logsoftc.sc_selp = 0; 84 logsoftc.sc_pgrp = 0; 85 #ifdef LOGDEBUG 86 xprintf("logclose: dev=0x%x\n", dev); 87 #endif 88 } 89 90 logread(dev, uio) 91 dev_t dev; 92 struct uio *uio; 93 { 94 register long l; 95 register u_int c; 96 register struct iovec *iov; 97 register int s; 98 int error = 0; 99 100 #ifdef LOGDEBUG 101 xprintf("logread: dev=0x%x\n", dev); 102 #endif 103 104 s = splhigh(); 105 while (msgbuf.msg_bufr == msgbuf.msg_bufx) { 106 if (logsoftc.sc_state & LOG_NBIO) { 107 splx(s); 108 return (EWOULDBLOCK); 109 } 110 logsoftc.sc_state |= LOG_RDWAIT; 111 sleep((caddr_t)&msgbuf, LOG_RDPRI); 112 } 113 splx(s); 114 logsoftc.sc_state &= ~LOG_RDWAIT; 115 116 while (uio->uio_resid > 0) { 117 l = msgbuf.msg_bufx - msgbuf.msg_bufr; 118 if (l < 0) 119 l = MSG_BSIZE - msgbuf.msg_bufr; 120 c = min((u_int) l, (u_int)uio->uio_resid); 121 #ifdef LOGDEBUG 122 xprintf("logread: bufx=%d, bufr=%d, l=%d, c=%d\n", 123 msgbuf.msg_bufx, msgbuf.msg_bufr, l, c); 124 #endif 125 if (c <= 0) 126 break; 127 error = uiomove((caddr_t)&msgbuf.msg_bufc[msgbuf.msg_bufr], 128 (int)c, UIO_READ, uio); 129 if (error) 130 break; 131 msgbuf.msg_bufr += c; 132 if (msgbuf.msg_bufr < 0 || msgbuf.msg_bufr >= MSG_BSIZE) 133 msgbuf.msg_bufr = 0; 134 } 135 return (error); 136 } 137 138 logselect(dev, rw) 139 dev_t dev; 140 int rw; 141 { 142 int s = splhigh(); 143 144 switch (rw) { 145 146 case FREAD: 147 if (msgbuf.msg_bufr != msgbuf.msg_bufx) 148 goto win; 149 #ifdef LOGDEBUG 150 if (logsoftc.sc_selp) 151 xprintf("logselect: collision\n"); 152 #endif 153 logsoftc.sc_selp = u.u_procp; 154 break; 155 156 case FWRITE: 157 #ifdef LOGDEBUG 158 xprintf("logselect: FWRITE\n"); 159 #endif 160 break; 161 } 162 splx(s); 163 return (0); 164 win: 165 splx(s); 166 return (1); 167 } 168 169 logwakeup() 170 { 171 172 if (!log_open) 173 return; 174 if (logsoftc.sc_selp) { 175 selwakeup(logsoftc.sc_selp, 0); 176 logsoftc.sc_selp = 0; 177 } 178 if (logsoftc.sc_state & LOG_ASYNC) 179 gsignal(logsoftc.sc_pgrp, SIGIO); 180 if (logsoftc.sc_state & LOG_RDWAIT) { 181 wakeup((caddr_t)&msgbuf); 182 logsoftc.sc_state &= ~LOG_RDWAIT; 183 } 184 } 185 186 /*ARGSUSED*/ 187 logioctl(com, data, flag) 188 caddr_t data; 189 { 190 long l; 191 int s; 192 193 switch (com) { 194 195 /* return number of characters immediately available */ 196 case FIONREAD: 197 s = splhigh(); 198 l = msgbuf.msg_bufx - msgbuf.msg_bufr; 199 splx(s); 200 if (l < 0) 201 l += MSG_BSIZE; 202 *(off_t *)data = l; 203 break; 204 205 case FIONBIO: 206 if (*(int *)data) 207 logsoftc.sc_state |= LOG_NBIO; 208 else 209 logsoftc.sc_state &= ~LOG_NBIO; 210 break; 211 212 case FIOASYNC: 213 if (*(int *)data) 214 logsoftc.sc_state |= LOG_ASYNC; 215 else 216 logsoftc.sc_state &= ~LOG_ASYNC; 217 break; 218 219 case TIOCSPGRP: 220 logsoftc.sc_pgrp = *(int *)data; 221 break; 222 223 case TIOCGPGRP: 224 *(int *)data = logsoftc.sc_pgrp; 225 break; 226 227 default: 228 return (-1); 229 } 230 return (0); 231 } 232