223 lines
7.2 KiB
C
223 lines
7.2 KiB
C
/* This file contains the rescue device driver (/dev/rescue)
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*
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* Changes:
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* Oct 21, 1992 created (Jorrit N. Herder)
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*/
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#include "../drivers.h"
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#include "../libdriver/driver.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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#define VERBOSE 0 /* enable/ disable messages */
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#define NR_DEVS 1 /* number of rescue devices */
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#define RESCUE_KBYTES 128 /* default size in kilobytes */
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PRIVATE struct device m_geom[NR_DEVS]; /* base and size of each device */
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PRIVATE int m_seg[NR_DEVS]; /* segment index 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( void m_init, (int argc, char **argv) );
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FORWARD _PROTOTYPE( char *m_name, (void) );
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FORWARD _PROTOTYPE( struct device *m_prepare, (int device) );
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FORWARD _PROTOTYPE( int m_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 m_do_open, (struct driver *dp, message *m_ptr) );
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FORWARD _PROTOTYPE( void m_geometry, (struct partition *entry) );
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/* Entry points to this driver. */
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PRIVATE struct driver m_dtab = {
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m_name, /* current device's name */
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m_do_open, /* open or mount */
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do_nop, /* nothing on a close */
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do_diocntl, /* standard I/O controls */
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m_prepare, /* prepare for I/O on a given minor device */
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m_transfer, /* do the I/O */
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nop_cleanup, /* no need to clean up */
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m_geometry, /* memory device "geometry" */
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nop_signal, /* system signals */
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nop_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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/*===========================================================================*
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* main *
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*===========================================================================*/
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PUBLIC int main(int argc, char **argv)
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{
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/* Main program. Initialize the rescue driver and start the main loop. */
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m_init(argc, argv);
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driver_task(&m_dtab);
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return(OK);
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}
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/*===========================================================================*
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* m_name *
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*===========================================================================*/
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PRIVATE char *m_name()
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{
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/* Return a name for the current device. */
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static char name[] = "rescue";
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return name;
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}
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/*===========================================================================*
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* m_prepare *
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*===========================================================================*/
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PRIVATE struct device *m_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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* m_transfer *
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*===========================================================================*/
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PRIVATE int m_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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int seg;
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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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int s;
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/* Get and check minor device number. */
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if ((unsigned) m_device > NR_DEVS - 1) return(ENXIO);
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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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/* Virtual copying. For rescue device. */
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if (position >= dv_size) return(OK); /* check for EOF */
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if (position + count > dv_size) count = dv_size - position;
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seg = m_seg[m_device];
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if (opcode == DEV_GATHER) { /* copy actual data */
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sys_vircopy(SELF,seg,position, proc_nr,D,user_vir, count);
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} else {
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sys_vircopy(proc_nr,D,user_vir, SELF,seg,position, count);
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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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* m_do_open *
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*===========================================================================*/
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PRIVATE int m_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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if (m_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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* m_init *
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*===========================================================================*/
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PRIVATE void m_init(argc,argv)
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int argc;
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char **argv;
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{
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/* Initialize this task. All minor devices are initialized one by one. */
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phys_bytes rescue_size;
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phys_bytes rescue_base;
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message m;
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int i, s;
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/* Initialize all rescue devices in a loop. */
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for (i=0; i< NR_DEVS; i++) {
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/* Determine size and base of rescue disks. See if rescue disk details
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* exist in the data store. If no memory for the rescue disk was claimed
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* yet, do it below.
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*/
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m.DS_KEY = (RESCUE_MAJOR << 8) + i;
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if (OK == (s = _taskcall(DS_PROC_NR, DS_RETRIEVE, &m))) {
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rescue_size = m.DS_VAL_L1;
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rescue_base = m.DS_VAL_L2;
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}
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else { /* no details known */
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if (argc>i+1) rescue_size = atoi(argv[i+1]) * 1024;
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else rescue_size = RESCUE_KBYTES * 1024;
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if (allocmem(rescue_size, &rescue_base) < 0) {
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report("RESCUE", "warning, allocmem failed", errno);
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rescue_size = 0;
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}
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}
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/* Now that we have the base and size of the rescue disk, set up all
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* data structures if the rescue has a positive (nonzero) size.
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*/
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if (rescue_size > 0) {
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/* Create a new remote segment to make virtual copies. */
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if (OK != (s=sys_segctl(&m_seg[i], (u16_t *) &s,
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(vir_bytes *) &s, rescue_base, rescue_size))) {
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panic("RESCUE","Couldn't install remote segment.",s);
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}
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/* Set the device geometry for the outside world. */
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m_geom[i].dv_base = cvul64(rescue_base);
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m_geom[i].dv_size = cvul64(rescue_size);
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/* Store the values in the data store for future retrieval. */
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m.DS_KEY = (RESCUE_MAJOR << 8) + i;
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m.DS_VAL_L1 = rescue_size;
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m.DS_VAL_L2 = rescue_base;
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if (OK != (s = _taskcall(DS_PROC_NR, DS_PUBLISH, &m))) {
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panic("RESCUE","Couldn't store rescue disk details at DS.",s);
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}
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#if VERBOSE
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printf("RESCUE disk %d (size %u/base %u) initialized\n",
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i, rescue_size, rescue_base);
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#endif
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}
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}
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}
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/*===========================================================================*
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* m_geometry *
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*===========================================================================*/
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PRIVATE void m_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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