247 lines
7.6 KiB
C
247 lines
7.6 KiB
C
/* This file contains the device dependent part of the drivers for the
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* following special files:
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* /dev/random - random number generator
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*/
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#include "../drivers.h"
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#include "../libdriver/driver.h"
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#include <sys/ioc_memory.h>
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#include "../../kernel/const.h"
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#include "../../kernel/config.h"
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#include "../../kernel/type.h"
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#include "assert.h"
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#include "random.h"
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#define NR_DEVS 1 /* number of minor devices */
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# define RANDOM_DEV 0 /* minor device for /dev/random */
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#define KRANDOM_PERIOD 1 /* ticks between krandom calls */
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PRIVATE struct device m_geom[NR_DEVS]; /* base and size of each device */
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PRIVATE int m_device; /* current device */
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extern int errno; /* error number for PM calls */
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FORWARD _PROTOTYPE( char *r_name, (void) );
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FORWARD _PROTOTYPE( struct device *r_prepare, (int device) );
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FORWARD _PROTOTYPE( int r_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 r_do_open, (struct driver *dp, message *m_ptr) );
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FORWARD _PROTOTYPE( void r_init, (void) );
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FORWARD _PROTOTYPE( int r_ioctl, (struct driver *dp, message *m_ptr) );
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FORWARD _PROTOTYPE( void r_geometry, (struct partition *entry) );
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FORWARD _PROTOTYPE( void r_random, (struct driver *dp, message *m_ptr) );
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/* Entry points to this driver. */
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PRIVATE struct driver r_dtab = {
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r_name, /* current device's name */
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r_do_open, /* open or mount */
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do_nop, /* nothing on a close */
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r_ioctl, /* specify ram disk geometry */
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r_prepare, /* prepare for I/O on a given minor device */
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r_transfer, /* do the I/O */
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nop_cleanup, /* no need to clean up */
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r_geometry, /* device "geometry" */
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nop_signal, /* system signals */
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r_random, /* get randomness from kernel (alarm) */
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nop_cancel,
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nop_select,
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NULL,
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NULL
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};
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/* Buffer for the /dev/random number generator. */
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#define RANDOM_BUF_SIZE 1024
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PRIVATE char random_buf[RANDOM_BUF_SIZE];
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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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r_init(); /* initialize the memory driver */
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driver_task(&r_dtab); /* start driver's main loop */
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return(OK);
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}
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/*===========================================================================*
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* r_name *
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*===========================================================================*/
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PRIVATE char *r_name()
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{
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/* Return a name for the current device. */
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static char name[] = "random";
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return name;
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}
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/*===========================================================================*
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* r_prepare *
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*===========================================================================*/
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PRIVATE struct device *r_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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m_device = device;
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return(&m_geom[device]);
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}
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/*===========================================================================*
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* r_transfer *
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*===========================================================================*/
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PRIVATE int r_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, left, chunk;
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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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/* Get minor device number and check for /dev/null. */
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dv = &m_geom[m_device];
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dv_size = cv64ul(dv->dv_size);
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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 (m_device) {
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/* Random number generator. Character instead of block device. */
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case RANDOM_DEV:
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if (opcode == DEV_GATHER && !random_isseeded())
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return(EAGAIN);
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left = count;
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while (left > 0) {
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chunk = (left > RANDOM_BUF_SIZE) ? RANDOM_BUF_SIZE : left;
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if (opcode == DEV_GATHER) {
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random_getbytes(random_buf, chunk);
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sys_vircopy(SELF, D, (vir_bytes) random_buf,
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proc_nr, D, user_vir, chunk);
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} else if (opcode == DEV_SCATTER) {
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sys_vircopy(proc_nr, D, user_vir,
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SELF, D, (vir_bytes) random_buf, chunk);
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random_putbytes(random_buf, chunk);
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}
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user_vir += chunk;
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left -= chunk;
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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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position += count;
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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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* r_do_open *
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*============================================================================*/
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PRIVATE int r_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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/* Check device number on open.
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*/
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if (r_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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* r_init *
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*===========================================================================*/
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PRIVATE void r_init()
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{
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/* Initialize this task. All minor devices are initialized one by one. */
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random_init();
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r_random(NULL, NULL); /* also set periodic timer */
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}
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/*===========================================================================*
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* r_ioctl *
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*===========================================================================*/
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PRIVATE int r_ioctl(dp, m_ptr)
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struct driver *dp; /* pointer to driver structure */
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message *m_ptr; /* pointer to control message */
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{
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struct device *dv;
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if ((dv = r_prepare(m_ptr->DEVICE)) == NIL_DEV) return(ENXIO);
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switch (m_ptr->REQUEST) {
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default:
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return(do_diocntl(&r_dtab, m_ptr));
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}
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return(OK);
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}
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/*============================================================================*
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* r_random *
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*============================================================================*/
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PRIVATE void r_random(dp, m_ptr)
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struct driver *dp; /* pointer to driver structure */
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message *m_ptr; /* pointer to alarm message */
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{
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/* Fetch random information from the kernel to update /dev/random. */
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int i, s, r_next, r_size, r_high;
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struct randomness krandom;
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if (OK != (s=sys_getrandomness(&krandom)))
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report("RANDOM", "sys_getrandomness failed", s);
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for (i= 0; i<RANDOM_SOURCES; i++)
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{
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r_next= krandom.bin[i].r_next;
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r_size= krandom.bin[i].r_size;
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r_high= r_next+r_size;
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if (r_high <= RANDOM_ELEMENTS)
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{
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random_update(i, &krandom.bin[i].r_buf[r_next], r_size);
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}
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else
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{
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assert(r_next < RANDOM_ELEMENTS);
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random_update(i, &krandom.bin[i].r_buf[r_next],
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RANDOM_ELEMENTS-r_next);
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random_update(i, &krandom.bin[i].r_buf[0],
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r_high-RANDOM_ELEMENTS);
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}
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}
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/* Schedule new alarm for next m_random call. */
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if (OK != (s=sys_setalarm(KRANDOM_PERIOD, 0)))
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report("RANDOM", "sys_setalarm failed", s);
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}
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/*============================================================================*
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* r_geometry *
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*============================================================================*/
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PRIVATE void r_geometry(entry)
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struct partition *entry;
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{
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/* Memory devices don't have a geometry, but the outside world insists. */
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entry->cylinders = div64u(m_geom[m_device].dv_size, SECTOR_SIZE) / (64 * 32);
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entry->heads = 64;
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entry->sectors = 32;
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}
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