480 lines
14 KiB
C
480 lines
14 KiB
C
/* This file contains a driver for:
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* /dev/klog - system log device
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*
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* Changes:
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* 21 July 2005 - Support for diagnostic messages (Jorrit N. Herder)
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* 7 July 2005 - Created (Ben Gras)
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*/
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#include "log.h"
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#include <sys/time.h>
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#include <sys/select.h>
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#include "../../kernel/const.h"
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#include "../../kernel/type.h"
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#define LOG_DEBUG 0 /* enable/ disable debugging */
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#define NR_DEVS 1 /* number of minor devices */
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#define MINOR_KLOG 0 /* /dev/klog */
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#define LOGINC(n, i) do { (n) = (((n) + (i)) % LOG_SIZE); } while(0)
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PUBLIC struct logdevice logdevices[NR_DEVS];
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PRIVATE struct device log_geom[NR_DEVS]; /* base and size of devices */
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PRIVATE int log_device = -1; /* current device */
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FORWARD _PROTOTYPE( char *log_name, (void) );
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FORWARD _PROTOTYPE( struct device *log_prepare, (int device) );
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FORWARD _PROTOTYPE( int log_transfer, (int proc_nr, int opcode, off_t position,
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iovec_t *iov, unsigned nr_req) );
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FORWARD _PROTOTYPE( int log_do_open, (struct driver *dp, message *m_ptr) );
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FORWARD _PROTOTYPE( int log_cancel, (struct driver *dp, message *m_ptr) );
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FORWARD _PROTOTYPE( int log_select, (struct driver *dp, message *m_ptr) );
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FORWARD _PROTOTYPE( void log_signal, (struct driver *dp, message *m_ptr) );
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FORWARD _PROTOTYPE( int log_other, (struct driver *dp, message *m_ptr) );
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FORWARD _PROTOTYPE( void log_geometry, (struct partition *entry) );
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FORWARD _PROTOTYPE( int subread, (struct logdevice *log, int count, int proc_nr, vir_bytes user_vir) );
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/* Entry points to this driver. */
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PRIVATE struct driver log_dtab = {
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log_name, /* current device's name */
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log_do_open, /* open or mount */
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do_nop, /* nothing on a close */
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do_nop, /* ioctl nop */
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log_prepare, /* prepare for I/O on a given minor device */
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log_transfer, /* do the I/O */
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nop_cleanup, /* no need to clean up */
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log_geometry, /* geometry */
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log_signal, /* handle system signal */
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nop_alarm, /* no alarm */
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log_cancel, /* CANCEL request */
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log_select, /* DEV_SELECT request */
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log_other, /* Unrecognized messages */
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NULL /* HW int */
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};
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extern int device_caller;
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/*===========================================================================*
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* main *
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*===========================================================================*/
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PUBLIC int main(void)
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{
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int i;
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for(i = 0; i < NR_DEVS; i++) {
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log_geom[i].dv_size = cvul64(LOG_SIZE);
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log_geom[i].dv_base = cvul64((long)logdevices[i].log_buffer);
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logdevices[i].log_size = logdevices[i].log_read =
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logdevices[i].log_write =
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logdevices[i].log_select_alerted =
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logdevices[i].log_selected =
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logdevices[i].log_select_ready_ops = 0;
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logdevices[i].log_proc_nr = 0;
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logdevices[i].log_revive_alerted = 0;
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}
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driver_task(&log_dtab);
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return(OK);
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}
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/*===========================================================================*
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* log_name *
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*===========================================================================*/
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PRIVATE char *log_name()
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{
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/* Return a name for the current device. */
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static char name[] = "log";
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return name;
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}
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/*===========================================================================*
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* log_prepare *
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*===========================================================================*/
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PRIVATE struct device *log_prepare(device)
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int device;
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{
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/* Prepare for I/O on a device: check if the minor device number is ok. */
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if (device < 0 || device >= NR_DEVS) return(NIL_DEV);
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log_device = device;
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return(&log_geom[device]);
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}
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/*===========================================================================*
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* subwrite *
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*===========================================================================*/
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PRIVATE int
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subwrite(struct logdevice *log, int count, int proc_nr, vir_bytes user_vir)
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{
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char *buf;
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int r;
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if (log->log_write + count > LOG_SIZE)
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count = LOG_SIZE - log->log_write;
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buf = log->log_buffer + log->log_write;
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if(proc_nr == SELF) {
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memcpy(buf, (char *) user_vir, count);
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}
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else {
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if((r=sys_vircopy(proc_nr,D,user_vir, SELF,D,(int)buf, count)) != OK)
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return r;
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}
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LOGINC(log->log_write, count);
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log->log_size += count;
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if(log->log_size > LOG_SIZE) {
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int overflow;
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overflow = log->log_size - LOG_SIZE;
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log->log_size -= overflow;
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LOGINC(log->log_read, overflow);
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}
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if(log->log_size > 0 && log->log_proc_nr && !log->log_revive_alerted) {
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/* Someone who was suspended on read can now
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* be revived.
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*/
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log->log_status = subread(log, log->log_iosize,
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log->log_proc_nr, log->log_user_vir);
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notify(log->log_source);
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log->log_revive_alerted = 1;
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}
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if(log->log_size > 0)
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log->log_select_ready_ops |= SEL_RD;
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if(log->log_size > 0 && log->log_selected &&
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!(log->log_select_alerted)) {
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/* Someone(s) who was/were select()ing can now
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* be awoken. If there was a blocking read (above),
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* this can only happen if the blocking read didn't
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* swallow all the data (log_size > 0).
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*/
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if(log->log_selected & SEL_RD) {
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notify(log->log_select_proc);
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log->log_select_alerted = 1;
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#if LOG_DEBUG
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printf("log notified %d\n", log->log_select_proc);
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#endif
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}
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}
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return count;
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}
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/*===========================================================================*
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* log_append *
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*===========================================================================*/
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PUBLIC void
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log_append(char *buf, int count)
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{
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int w = 0, skip = 0;
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if(count < 1) return;
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if(count > LOG_SIZE) skip = count - LOG_SIZE;
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count -= skip;
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buf += skip;
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w = subwrite(&logdevices[0], count, SELF, (vir_bytes) buf);
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if(w > 0 && w < count)
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subwrite(&logdevices[0], count-w, SELF, (vir_bytes) buf+w);
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return;
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}
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/*===========================================================================*
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* subread *
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*===========================================================================*/
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PRIVATE int
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subread(struct logdevice *log, int count, int proc_nr, vir_bytes user_vir)
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{
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char *buf;
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int r;
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if (count > log->log_size)
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count = log->log_size;
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if (log->log_read + count > LOG_SIZE)
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count = LOG_SIZE - log->log_read;
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buf = log->log_buffer + log->log_read;
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if((r=sys_vircopy(SELF,D,(int)buf,proc_nr,D,user_vir, count)) != OK)
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return r;
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LOGINC(log->log_read, count);
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log->log_size -= count;
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return count;
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}
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/*===========================================================================*
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* log_transfer *
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*===========================================================================*/
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PRIVATE int log_transfer(proc_nr, opcode, position, iov, nr_req)
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int proc_nr; /* process doing the request */
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int opcode; /* DEV_GATHER or DEV_SCATTER */
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off_t position; /* offset on device to read or write */
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iovec_t *iov; /* pointer to read or write request vector */
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unsigned nr_req; /* length of request vector */
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{
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/* Read or write one the driver's minor devices. */
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unsigned count;
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vir_bytes user_vir;
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struct device *dv;
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unsigned long dv_size;
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int accumulated_read = 0;
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struct logdevice *log;
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static int f;
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if(log_device < 0 || log_device >= NR_DEVS)
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return EIO;
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/* Get minor device number and check for /dev/null. */
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dv = &log_geom[log_device];
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dv_size = cv64ul(dv->dv_size);
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log = &logdevices[log_device];
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while (nr_req > 0) {
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/* How much to transfer and where to / from. */
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count = iov->iov_size;
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user_vir = iov->iov_addr;
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switch (log_device) {
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case MINOR_KLOG:
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if (opcode == DEV_GATHER) {
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if (log->log_proc_nr || count < 1) {
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/* There's already someone hanging to read, or
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* no real I/O requested.
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*/
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return(OK);
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}
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if (!log->log_size) {
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if(accumulated_read)
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return OK;
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/* No data available; let caller block. */
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log->log_proc_nr = proc_nr;
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log->log_iosize = count;
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log->log_user_vir = user_vir;
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log->log_revive_alerted = 0;
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/* Device_caller is a global in drivers library. */
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log->log_source = device_caller;
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#if LOG_DEBUG
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printf("blocked %d (%d)\n",
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log->log_source, log->log_proc_nr);
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#endif
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return(SUSPEND);
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}
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count = subread(log, count, proc_nr, user_vir);
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if(count < 0) {
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return count;
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}
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accumulated_read += count;
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} else {
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count = subwrite(log, count, proc_nr, user_vir);
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if(count < 0)
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return count;
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}
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break;
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/* Unknown (illegal) minor device. */
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default:
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return(EINVAL);
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}
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/* Book the number of bytes transferred. */
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iov->iov_addr += count;
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if ((iov->iov_size -= count) == 0) { iov++; nr_req--; }
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}
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return(OK);
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}
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/*============================================================================*
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* log_do_open *
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*============================================================================*/
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PRIVATE int log_do_open(dp, m_ptr)
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struct driver *dp;
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message *m_ptr;
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{
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if (log_prepare(m_ptr->DEVICE) == NIL_DEV) return(ENXIO);
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return(OK);
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}
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/*============================================================================*
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* log_geometry *
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*============================================================================*/
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PRIVATE void log_geometry(entry)
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struct partition *entry;
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{
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/* take a page from the fake memory device geometry */
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entry->heads = 64;
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entry->sectors = 32;
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entry->cylinders = div64u(log_geom[log_device].dv_size, SECTOR_SIZE) /
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(entry->heads * entry->sectors);
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}
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/*============================================================================*
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* log_cancel *
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*============================================================================*/
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PRIVATE int log_cancel(dp, m_ptr)
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struct driver *dp;
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message *m_ptr;
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{
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int d;
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d = m_ptr->TTY_LINE;
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if(d < 0 || d >= NR_DEVS)
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return EINVAL;
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logdevices[d].log_proc_nr = 0;
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logdevices[d].log_revive_alerted = 0;
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return(OK);
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}
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/*============================================================================*
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* do_status *
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*============================================================================*/
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PRIVATE void do_status(message *m_ptr)
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{
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int d;
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message m;
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/* Caller has requested pending status information, which currently
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* can be pending available select()s, or REVIVE events. One message
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* is returned for every event, or DEV_NO_STATUS if no (more) events
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* are to be returned.
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*/
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for(d = 0; d < NR_DEVS; d++) {
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/* Check for revive callback. */
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if(logdevices[d].log_proc_nr && logdevices[d].log_revive_alerted
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&& logdevices[d].log_source == m_ptr->m_source) {
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m.m_type = DEV_REVIVE;
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m.REP_PROC_NR = logdevices[d].log_proc_nr;
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m.REP_STATUS = logdevices[d].log_status;
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send(m_ptr->m_source, &m);
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logdevices[d].log_proc_nr = 0;
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logdevices[d].log_revive_alerted = 0;
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#if LOG_DEBUG
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printf("revived %d with %d bytes\n",
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m.REP_PROC_NR, m.REP_STATUS);
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#endif
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return;
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}
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/* Check for select callback. */
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if(logdevices[d].log_selected && logdevices[d].log_select_proc == m_ptr->m_source
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&& logdevices[d].log_select_alerted) {
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m.m_type = DEV_IO_READY;
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m.DEV_SEL_OPS = logdevices[d].log_select_ready_ops;
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m.DEV_MINOR = d;
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#if LOG_DEBUG
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printf("select sending sent\n");
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#endif
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send(m_ptr->m_source, &m);
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logdevices[d].log_selected &= ~logdevices[d].log_select_ready_ops;
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logdevices[d].log_select_alerted = 0;
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#if LOG_DEBUG
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printf("select send sent\n");
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#endif
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return;
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}
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}
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/* No event found. */
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m.m_type = DEV_NO_STATUS;
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send(m_ptr->m_source, &m);
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return;
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}
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/*============================================================================*
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* log_signal *
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*============================================================================*/
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PRIVATE void log_signal(dp, m_ptr)
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struct driver *dp;
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message *m_ptr;
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{
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sigset_t sigset = m_ptr->NOTIFY_ARG;
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if (sigismember(&sigset, SIGKMESS)) {
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do_new_kmess(m_ptr);
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}
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}
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/*============================================================================*
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* log_other *
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*============================================================================*/
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PRIVATE int log_other(dp, m_ptr)
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struct driver *dp;
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message *m_ptr;
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{
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int r;
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/* This function gets messages that the generic driver doesn't
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* understand.
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*/
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switch(m_ptr->m_type) {
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case DIAGNOSTICS: {
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r = do_diagnostics(m_ptr);
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break;
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}
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case DEV_STATUS: {
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do_status(m_ptr);
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r = EDONTREPLY;
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break;
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}
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case NOTIFY_FROM(TTY_PROC_NR):
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do_new_kmess(m_ptr);
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r = EDONTREPLY;
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break;
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default:
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r = EINVAL;
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break;
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}
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return r;
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}
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/*============================================================================*
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* log_select *
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*============================================================================*/
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PRIVATE int log_select(dp, m_ptr)
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struct driver *dp;
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message *m_ptr;
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{
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int d, ready_ops = 0, ops = 0;
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d = m_ptr->TTY_LINE;
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if(d < 0 || d >= NR_DEVS) {
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#if LOG_DEBUG
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printf("line %d? EINVAL\n", d);
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#endif
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return EINVAL;
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}
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ops = m_ptr->PROC_NR & (SEL_RD|SEL_WR|SEL_ERR);
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/* Read blocks when there is no log. */
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if((m_ptr->PROC_NR & SEL_RD) && logdevices[d].log_size > 0) {
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#if LOG_DEBUG
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printf("log can read; size %d\n", logdevices[d].log_size);
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#endif
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ready_ops |= SEL_RD; /* writes never block */
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}
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/* Write never blocks. */
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if(m_ptr->PROC_NR & SEL_WR) ready_ops |= SEL_WR;
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/* Enable select calback if no operations were
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* ready to go, but operations were requested,
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* and notify was enabled.
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*/
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if((m_ptr->PROC_NR & SEL_NOTIFY) && ops && !ready_ops) {
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logdevices[d].log_selected |= ops;
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logdevices[d].log_select_proc = m_ptr->m_source;
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#if LOG_DEBUG
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printf("log setting selector.\n");
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#endif
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}
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#if LOG_DEBUG
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printf("log returning ops %d\n", ready_ops);
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#endif
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return(ready_ops);
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}
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