1 /* subr_log.c 6.4 85/03/18 */ 2 3 /* 4 * Error log buffer for kernel printf's. 5 */ 6 7 #include "param.h" 8 #include "dir.h" 9 #include "user.h" 10 #include "proc.h" 11 #include "ioctl.h" 12 #include "msgbuf.h" 13 #include "file.h" 14 #include "errno.h" 15 16 #define LOG_RDPRI (PZERO + 1) 17 18 #define LOG_NBIO 0x02 19 #define LOG_ASYNC 0x04 20 #define LOG_RDWAIT 0x08 21 22 struct logsoftc { 23 int sc_state; /* see above for possibilities */ 24 struct proc *sc_selp; /* process waiting on select call */ 25 int sc_pgrp; /* process group for async I/O */ 26 } logsoftc; 27 28 int log_open; /* also used in log() */ 29 30 #ifdef LOGDEBUG 31 /*VARARGS1*/ 32 xprintf(fmt, x1) 33 char *fmt; 34 unsigned x1; 35 { 36 37 prf(fmt, &x1, 1, (struct tty *)0); 38 } 39 #endif 40 41 logopen(dev) 42 dev_t dev; 43 { 44 45 #ifdef LOGDEBUG 46 xprintf("logopen: dev=0x%x\n", dev); 47 #endif 48 if (log_open) 49 return (EBUSY); 50 log_open = 1; 51 logsoftc.sc_selp = 0; 52 logsoftc.sc_pgrp = u.u_procp->p_pgrp; 53 /* 54 * Potential race here with putchar() but since putchar should be 55 * called by autoconf, msg_magic should be initialized by the time 56 * we get here. 57 */ 58 if (msgbuf.msg_magic != MSG_MAGIC) { 59 register int i; 60 61 msgbuf.msg_magic = MSG_MAGIC; 62 msgbuf.msg_bufx = msgbuf.msg_bufr = 0; 63 for (i=0; i < MSG_BSIZE; i++) 64 msgbuf.msg_bufc[i] = 0; 65 } 66 #ifdef LOGDEBUG 67 xprintf("logopen: bufx=%d, bufr=%d\n", msgbuf.msg_bufx, msgbuf.msg_bufr); 68 #endif 69 return (0); 70 } 71 72 logclose(dev, flag) 73 dev_t dev; 74 { 75 log_open = 0; 76 logsoftc.sc_state = 0; 77 logsoftc.sc_selp = 0; 78 logsoftc.sc_pgrp = 0; 79 #ifdef LOGDEBUG 80 xprintf("logclose: dev=0x%x\n", dev); 81 #endif 82 } 83 84 logread(dev, uio) 85 dev_t dev; 86 struct uio *uio; 87 { 88 register long l; 89 register u_int c; 90 register struct iovec *iov; 91 register int s; 92 int error = 0; 93 94 #ifdef LOGDEBUG 95 xprintf("logread: dev=0x%x\n", dev); 96 #endif 97 98 s = splhigh(); 99 while (msgbuf.msg_bufr == msgbuf.msg_bufx) { 100 if (logsoftc.sc_state & LOG_NBIO) { 101 splx(s); 102 return (EWOULDBLOCK); 103 } 104 logsoftc.sc_state |= LOG_RDWAIT; 105 sleep((caddr_t)&msgbuf, LOG_RDPRI); 106 } 107 splx(s); 108 logsoftc.sc_state &= ~LOG_RDWAIT; 109 110 while (uio->uio_resid > 0) { 111 l = msgbuf.msg_bufx - msgbuf.msg_bufr; 112 if (l < 0) 113 l = MSG_BSIZE - msgbuf.msg_bufr; 114 c = min((u_int) l, (u_int)uio->uio_resid); 115 #ifdef LOGDEBUG 116 xprintf("logread: bufx=%d, bufr=%d, l=%d, c=%d\n", 117 msgbuf.msg_bufx, msgbuf.msg_bufr, l, c); 118 #endif 119 if (c <= 0) 120 break; 121 error = uiomove((caddr_t)&msgbuf.msg_bufc[msgbuf.msg_bufr], 122 (int)c, UIO_READ, uio); 123 if (error) 124 break; 125 msgbuf.msg_bufr += c; 126 if (msgbuf.msg_bufr < 0 || msgbuf.msg_bufr >= MSG_BSIZE) 127 msgbuf.msg_bufr = 0; 128 } 129 return (error); 130 } 131 132 logselect(dev, rw) 133 dev_t dev; 134 int rw; 135 { 136 int s = splhigh(); 137 138 switch (rw) { 139 140 case FREAD: 141 if (msgbuf.msg_bufr != msgbuf.msg_bufx) 142 goto win; 143 #ifdef LOGDEBUG 144 if (logsoftc.sc_selp) 145 xprintf("logselect: collision\n"); 146 #endif 147 logsoftc.sc_selp = u.u_procp; 148 break; 149 150 case FWRITE: 151 #ifdef LOGDEBUG 152 xprintf("logselect: FWRITE\n"); 153 #endif 154 break; 155 } 156 splx(s); 157 return (0); 158 win: 159 splx(s); 160 return (1); 161 } 162 163 logwakeup() 164 { 165 166 if (!log_open) 167 return; 168 if (logsoftc.sc_selp) { 169 selwakeup(logsoftc.sc_selp, 0); 170 logsoftc.sc_selp = 0; 171 } 172 if (logsoftc.sc_state & LOG_ASYNC) 173 gsignal(logsoftc.sc_pgrp, SIGIO); 174 if (logsoftc.sc_state & LOG_RDWAIT) { 175 wakeup((caddr_t)&msgbuf); 176 logsoftc.sc_state &= ~LOG_RDWAIT; 177 } 178 } 179 180 /*ARGSUSED*/ 181 logioctl(com, data, flag) 182 caddr_t data; 183 { 184 long l; 185 int s; 186 187 switch (com) { 188 189 /* return number of characters immediately available */ 190 case FIONREAD: 191 s = splhigh(); 192 l = msgbuf.msg_bufx - msgbuf.msg_bufr; 193 splx(s); 194 if (l < 0) 195 l += MSG_BSIZE; 196 *(off_t *)data = l; 197 break; 198 199 case FIONBIO: 200 if (*(int *)data) 201 logsoftc.sc_state |= LOG_NBIO; 202 else 203 logsoftc.sc_state &= ~LOG_NBIO; 204 break; 205 206 case FIOASYNC: 207 if (*(int *)data) 208 logsoftc.sc_state |= LOG_ASYNC; 209 else 210 logsoftc.sc_state &= ~LOG_ASYNC; 211 break; 212 213 case TIOCSPGRP: 214 logsoftc.sc_pgrp = *(int *)data; 215 break; 216 217 case TIOCGPGRP: 218 *(int *)data = logsoftc.sc_pgrp; 219 break; 220 221 default: 222 return (-1); 223 } 224 return (0); 225 } 226