source: trunk/minix/drivers/rescue/rescue.c@ 15

Last change on this file since 15 was 9, checked in by Mattia Monga, 14 years ago

Minix 3.1.2a
File size: 7.2 KB
Line 
1/* This file contains the rescue device driver (/dev/rescue)
2 *
3 * Changes:
4 * Oct 21, 1992 created (Jorrit N. Herder)
5 */
6
7#include "../drivers.h"
8#include "../libdriver/driver.h"
9#include "../../kernel/const.h"
10#include "../../kernel/config.h"
11#include "../../kernel/type.h"
12
13#define VERBOSE 0 /* enable/ disable messages */
14#define NR_DEVS 1 /* number of rescue devices */
15#define RESCUE_KBYTES 128 /* default size in kilobytes */
16
17PRIVATE struct device m_geom[NR_DEVS]; /* base and size of each device */
18PRIVATE int m_seg[NR_DEVS]; /* segment index of each device */
19PRIVATE int m_device; /* current device */
20
21extern int errno; /* error number for PM calls */
22
23FORWARD _PROTOTYPE( void m_init, (int argc, char **argv) );
24FORWARD _PROTOTYPE( char *m_name, (void) );
25FORWARD _PROTOTYPE( struct device *m_prepare, (int device) );
26FORWARD _PROTOTYPE( int m_transfer, (int proc_nr, int opcode, off_t position,
27 iovec_t *iov, unsigned nr_req) );
28FORWARD _PROTOTYPE( int m_do_open, (struct driver *dp, message *m_ptr) );
29FORWARD _PROTOTYPE( void m_geometry, (struct partition *entry) );
30
31/* Entry points to this driver. */
32PRIVATE struct driver m_dtab = {
33 m_name, /* current device's name */
34 m_do_open, /* open or mount */
35 do_nop, /* nothing on a close */
36 do_diocntl, /* standard I/O controls */
37 m_prepare, /* prepare for I/O on a given minor device */
38 m_transfer, /* do the I/O */
39 nop_cleanup, /* no need to clean up */
40 m_geometry, /* memory device "geometry" */
41 nop_signal, /* system signals */
42 nop_alarm,
43 nop_cancel,
44 nop_select,
45 NULL,
46 NULL
47};
48
49
50/*===========================================================================*
51 * main *
52 *===========================================================================*/
53PUBLIC int main(int argc, char **argv)
54{
55/* Main program. Initialize the rescue driver and start the main loop. */
56 m_init(argc, argv);
57 driver_task(&m_dtab);
58 return(OK);
59}
60
61/*===========================================================================*
62 * m_name *
63 *===========================================================================*/
64PRIVATE char *m_name()
65{
66/* Return a name for the current device. */
67 static char name[] = "rescue";
68 return name;
69}
70
71/*===========================================================================*
72 * m_prepare *
73 *===========================================================================*/
74PRIVATE struct device *m_prepare(device)
75int device;
76{
77/* Prepare for I/O on a device: check if the minor device number is ok. */
78 if (device < 0 || device >= NR_DEVS) return(NIL_DEV);
79 m_device = device;
80
81 return(&m_geom[device]);
82}
83
84/*===========================================================================*
85 * m_transfer *
86 *===========================================================================*/
87PRIVATE int m_transfer(proc_nr, opcode, position, iov, nr_req)
88int proc_nr; /* process doing the request */
89int opcode; /* DEV_GATHER or DEV_SCATTER */
90off_t position; /* offset on device to read or write */
91iovec_t *iov; /* pointer to read or write request vector */
92unsigned nr_req; /* length of request vector */
93{
94/* Read or write one the driver's minor devices. */
95 int seg;
96 unsigned count, left, chunk;
97 vir_bytes user_vir;
98 struct device *dv;
99 unsigned long dv_size;
100 int s;
101
102 /* Get and check minor device number. */
103 if ((unsigned) m_device > NR_DEVS - 1) return(ENXIO);
104 dv = &m_geom[m_device];
105 dv_size = cv64ul(dv->dv_size);
106
107 while (nr_req > 0) {
108
109 /* How much to transfer and where to / from. */
110 count = iov->iov_size;
111 user_vir = iov->iov_addr;
112
113 /* Virtual copying. For rescue device. */
114 if (position >= dv_size) return(OK); /* check for EOF */
115 if (position + count > dv_size) count = dv_size - position;
116 seg = m_seg[m_device];
117
118 if (opcode == DEV_GATHER) { /* copy actual data */
119 sys_vircopy(SELF,seg,position, proc_nr,D,user_vir, count);
120 } else {
121 sys_vircopy(proc_nr,D,user_vir, SELF,seg,position, count);
122 }
123
124 /* Book the number of bytes transferred. */
125 position += count;
126 iov->iov_addr += count;
127 if ((iov->iov_size -= count) == 0) { iov++; nr_req--; }
128
129 }
130 return(OK);
131}
132
133/*===========================================================================*
134 * m_do_open *
135 *===========================================================================*/
136PRIVATE int m_do_open(dp, m_ptr)
137struct driver *dp;
138message *m_ptr;
139{
140/* Check device number on open. */
141 if (m_prepare(m_ptr->DEVICE) == NIL_DEV) return(ENXIO);
142 return(OK);
143}
144
145/*===========================================================================*
146 * m_init *
147 *===========================================================================*/
148PRIVATE void m_init(argc,argv)
149int argc;
150char **argv;
151{
152 /* Initialize this task. All minor devices are initialized one by one. */
153 phys_bytes rescue_size;
154 phys_bytes rescue_base;
155 message m;
156 int i, s;
157
158 /* Initialize all rescue devices in a loop. */
159 for (i=0; i< NR_DEVS; i++) {
160
161 /* Determine size and base of rescue disks. See if rescue disk details
162 * exist in the data store. If no memory for the rescue disk was claimed
163 * yet, do it below.
164 */
165 m.DS_KEY = (RESCUE_MAJOR << 8) + i;
166 if (OK == (s = _taskcall(DS_PROC_NR, DS_RETRIEVE, &m))) {
167 rescue_size = m.DS_VAL_L1;
168 rescue_base = m.DS_VAL_L2;
169 }
170 else { /* no details known */
171 if (argc>i+1) rescue_size = atoi(argv[i+1]) * 1024;
172 else rescue_size = RESCUE_KBYTES * 1024;
173
174 if (allocmem(rescue_size, &rescue_base) < 0) {
175 report("RESCUE", "warning, allocmem failed", errno);
176 rescue_size = 0;
177 }
178 }
179
180 /* Now that we have the base and size of the rescue disk, set up all
181 * data structures if the rescue has a positive (nonzero) size.
182 */
183 if (rescue_size > 0) {
184
185 /* Create a new remote segment to make virtual copies. */
186 if (OK != (s=sys_segctl(&m_seg[i], (u16_t *) &s,
187 (vir_bytes *) &s, rescue_base, rescue_size))) {
188 panic("RESCUE","Couldn't install remote segment.",s);
189 }
190
191 /* Set the device geometry for the outside world. */
192 m_geom[i].dv_base = cvul64(rescue_base);
193 m_geom[i].dv_size = cvul64(rescue_size);
194
195 /* Store the values in the data store for future retrieval. */
196 m.DS_KEY = (RESCUE_MAJOR << 8) + i;
197 m.DS_VAL_L1 = rescue_size;
198 m.DS_VAL_L2 = rescue_base;
199 if (OK != (s = _taskcall(DS_PROC_NR, DS_PUBLISH, &m))) {
200 panic("RESCUE","Couldn't store rescue disk details at DS.",s);
201 }
202
203#if VERBOSE
204 printf("RESCUE disk %d (size %u/base %u) initialized\n",
205 i, rescue_size, rescue_base);
206#endif
207 }
208 }
209}
210
211/*===========================================================================*
212 * m_geometry *
213 *===========================================================================*/
214PRIVATE void m_geometry(entry)
215struct partition *entry;
216{
217 /* Memory devices don't have a geometry, but the outside world insists. */
218 entry->cylinders = div64u(m_geom[m_device].dv_size, SECTOR_SIZE) / (64 * 32);
219 entry->heads = 64;
220 entry->sectors = 32;
221}
222
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