Minix1.5/commands/mkfs.c
/* mkfs - make the MINIX filesystem Authors: A. Tanenbaum & P. Ogilvie */
/* Andy Tanenbaum & Paul Ogilvie, June 1986
*
* This program was initially designed to build a filesystem
* with blocksize = zonesize. During the course of time the
* program is being converted to handle zone_size > blocksize
* but this isn't complete yet. Where routines can handle the
* situation this is mentioned in the comment.
*
* To compile this program for MS-DOS, use: cc -DDOS mkfs.c diskio.asm
* To compile this program for UNIX, use: cc -DUNIX mkfs.c
* To compile this program for MINIX, use: cc mkfs.c
*/
#include <sys/types.h>
#include <limits.h>
#include <minix/config.h>
#include <minix/const.h>
#include <minix/type.h>
#include "../fs/const.h"
#undef EXTERN
#define EXTERN /* get rid of EXTERN by making it null */
#include "../fs/type.h"
#include "../fs/super.h"
#include <fcntl.h>
#include <sys/stat.h>
#include <unistd.h>
#include <stdlib.h>
#include <stdio.h>
#ifndef DOS
#ifndef UNIX
#undef printf /* printf is a macro for printk */
#define UNIX
#endif
#endif
#define INODE_MAP 2
#define MAX_TOKENS 10
#define LINE_LEN 200
#define BIN 2
#define BINGRP 2
#define BIT_MAP_SHIFT 13
#define N_BLOCKS 0x10000L /* must be multiple of 8 */
#ifdef DOS
maybedefine O_RDONLY 4 /* O_RDONLY | BINARY_BIT */
maybedefine BWRITE 5 /* O_WRONLY | BINARY_BIT */
#endif
#if (MACHINE == ATARI)
int isdev;
#endif
int next_zone, next_inode, zone_size, zone_shift = 0, zoff;
unsigned nrblocks;
int inode_offset, nrinodes, lct = 1, disk, fd, print = 0, file = 0;
int override = 0, simple = 0, dflag;
int donttest; /* skip test if it fits on medium */
long current_time, bin_time;
char zero[BLOCK_SIZE], *lastp;
char umap[(N_BLOCKS + 8) / 8]; /* bit map tells if block read yet */
int zone_map = 3; /* where is zone map? (depends on # inodes) */
FILE *proto;
char gwarning[] = {65, 46, 83, 46, 84, 97, 110, 101, 110, 98, 97, 117, 109, 10};
/*================================================================
* mkfs - make filesystem
*===============================================================*/
main(argc, argv)
int argc;
char *argv[];
{
int i, mode, usrid, grpid, badusage = 0;
unsigned zones, inodes;
unsigned long blocks;
char *token[MAX_TOKENS], line[LINE_LEN];
FILE *fopen();
long time(), ls;
struct stat statbuf;
/* Get two times, the current time and the mod time of the binary of
* mkfs itself. When the -d flag is used, the later time is put into
* the i_mtimes of all the files. This feature is useful when
* producing a set of file systems, and one wants all the times to be
* identical. First you set the time of the mkfs binary to what you
* want, then go. */
current_time = time(0L); /* time mkfs is being run */
stat(argv[0], &statbuf);
bin_time = statbuf.st_mtime; /* time when mkfs binary was last modified */
/* Process parameters and switches */
if (argc != 3 && argc != 4) badusage = 1;
if (stat(argv[argc - 1], &statbuf) == 0) {
if ((statbuf.st_mode & S_IFMT) != S_IFREG) badusage = 1;
}
if (badusage) {
write(2, "Usage: mkfs [-ldt] special proto\n", 33);
exit(1);
}
while (--argc) {
switch (argv[argc][0]) {
case '-':
while (*++argv[argc]) switch (*argv[argc]) {
case 'l':
case 'L': print = 1; break;
case 'o':
case 'O':
override = 1;
break;
case 'd':
case 'D':
current_time = bin_time;
dflag = 1;
break;
case 't':
case 'T':
donttest = 1;
break;
default:
printf("Bad switch %c, ignored.\n", *argv[argc]);
}
break;
default:
/* Process proto & special */
proto = fopen(argv[argc], "r");
if (proto != (FILE *) NULL) {
/* Prototype file is readable. */
getline(line, token); /* skip boot block info. */
/* Read the line with the block and inode counts. */
getline(line, token);
blocks = atol(token[0]);
if (blocks > N_BLOCKS)
pexit("Block count too large");
inodes = atoi(token[1]);
/* Process mode line for root directory. */
getline(line, token);
mode = mode_con(token[0]);
usrid = atoi(token[1]);
grpid = atoi(token[2]);
} else {
/* Maybe the prototype file is just a size.
* Check for that. */
blocks = atol(argv[argc]);
if (blocks < 4) pexit("Can't open prototype file");
if (blocks > N_BLOCKS)
pexit("Block count too large");
/* Ok, make simple file system of given size,
* using defaults. */
inodes = (blocks / 3) + 8; /* default is 3
* blocks/file */
mode = 040777;
usrid = BIN;
grpid = BINGRP;
simple = 1;
}
/* Open special */
argc--;
special(argv[argc]);
nrblocks = blocks;
nrinodes = inodes;
} /* end switch */
} /* end while */
#ifdef UNIX
if (!donttest) {
static short testb[BLOCK_SIZE / sizeof(short)];
/* Try writing the last block of partition or diskette. */
ls = lseek(fd, ((long) blocks - 1L) * BLOCK_SIZE, SEEK_SET);
testb[0] = 0x3245;
testb[1] = 0x11FF;
if (write(fd, (char *) testb, BLOCK_SIZE) != BLOCK_SIZE)
pexit("File system is too big for minor device");
sync(); /* flush write, so if error next read fails */
lseek(fd, ((long) blocks - 1L) * BLOCK_SIZE, SEEK_SET);
testb[0] = 0;
testb[1] = 0;
i = read(fd, (char *) testb, BLOCK_SIZE);
if (i != BLOCK_SIZE || testb[0] != 0x3245 || testb[1] != 0x11FF)
pexit("File system is too big for minor device");
lseek(fd, ((long) blocks - 1L) * BLOCK_SIZE, SEEK_SET);
testb[0] = 0;
testb[1] = 0;
if (write(fd, (char *) testb, BLOCK_SIZE) != BLOCK_SIZE)
pexit("File system is too big for minor device");
lseek(fd, 0L, SEEK_SET);
}
#endif
/* Make the file-system */
cache_init();
#if (MACHINE == ATARI)
if (isdev) {
char block0[BLOCK_SIZE];
get_block(0, block0);
/* need to read twice; first time gets an empty block */
get_block(0, block0);
/* zero parts of the boot block so the disk won't be recognized as
a tos disk any more. */
block0[0] = block0[1] = 0; /* branch code to boot code */
strncpy(&block0[2], "MINIX ", 6);
block0[16] = 0; /* number of FATS */
block0[17] = block0[18] = 0;/* number of dir entries */
block0[22] = block0[23] = 0;/* sectors/FAT */
bzero(&block0[30], 480); /* boot code */
put_block(0, block0);
}
else
#endif
put_block(0, zero); /* Write a null boot block. */
zone_shift = 0; /* for future use */
zones = nrblocks >> zone_shift;
super(zones, inodes);
i = alloc_inode(mode, usrid, grpid);
rootdir(i);
if (simple == 0) eat_dir(i);
if (print) print_fs();
flush();
exit(0);
} /* end main */
/*================================================================
* super - construct a superblock
*===============================================================*/
super(zones, inodes)
unsigned zones, inodes;
{
unsigned int i, inodeblks, initblks, initzones, nrzones;
unsigned int bit_map_len, b_needed, b_allocated, residual;
long zo;
struct super_block *sup;
char buf[BLOCK_SIZE], *cp;
sup = (struct super_block *) buf;
sup->s_ninodes = inodes;
sup->s_nzones = zones;
sup->s_imap_blocks = bitmapsize(1 + inodes);
sup->s_zmap_blocks = bitmapsize(zones);
inode_offset = sup->s_imap_blocks + sup->s_zmap_blocks + 2;
inodeblks = (inodes + INODES_PER_BLOCK - 1) / INODES_PER_BLOCK;
initblks = inode_offset + inodeblks;
initzones = (initblks + (1 << zone_shift) - 1) >> zone_shift;
nrzones = nrblocks >> zone_shift;
sup->s_firstdatazone = (initblks + (1 << zone_shift) - 1) >> zone_shift;
zoff = sup->s_firstdatazone - 1;
sup->s_log_zone_size = zone_shift;
sup->s_magic = SUPER_MAGIC; /* identify super blocks */
zo = 7L + (long) NR_INDIRECTS
+ (long) NR_INDIRECTS *NR_INDIRECTS;
sup->s_max_size = zo * BLOCK_SIZE;
zone_size = 1 << zone_shift; /* nr of blocks per zone */
for (cp = buf + sizeof(*sup); cp < &buf[BLOCK_SIZE]; cp++) *cp = 0;
put_block(1, buf);
/* Clear maps and inodes. */
for (i = 2; i < initblks; i++) put_block(i, zero);
next_zone = sup->s_firstdatazone;
next_inode = 1;
/* Mark all bits beyond the end of the legal inodes and zones as
* allocated. Unfortunately, the coding the bit maps is inconsistent.
* The rules are: For inodes: Every i-node occupies a bit map slot,
* even i-node 0 The first i-node on the disk is i-node 1, not 0 For
* zones: Zone map bit 0 is for the last i-node block on disk
* The first zone available goes with bit 1 in the map
*
* Thus for i-nodes, every i-node, starting at 0 occupies a bit map
* slot, but for zones, only those starting with the final i-node
* block occupy bit slots. This is inconsistent. In retrospect it
* would might have been simpler to have bit 0 of the zone map be
* zone 0 on the disk. Although this would have increased the zone
* bit map by a few dozen bits, it would have prevented a number of
* bugs in the early days. This is an example of what happens when
* one ignores the maxim: First make it work, then make it optimal.
* For both maps, 0 = available, 1 = in use. */
/* Mark bits beyond end of inodes as allocated. */
bit_map_len = nrinodes + 1; /* # bits needed in map */
residual = bit_map_len % (8 * BLOCK_SIZE);
if (residual == 0) residual = 8 * BLOCK_SIZE;
b_needed = bitmapsize(bit_map_len);
zone_map += b_needed - 1; /* if imap > 1, adjust start of zone map */
insert_bit(INODE_MAP + b_needed - 1, residual, 8 * BLOCK_SIZE - residual);
bit_map_len = nrzones - initzones + 1; /* # bits needed in map */
residual = bit_map_len % (8 * BLOCK_SIZE);
if (residual == 0) residual = 8 * BLOCK_SIZE;
b_needed = bitmapsize(bit_map_len);
b_allocated = bitmapsize(nrzones);
insert_bit(zone_map + b_needed - 1, residual, 8 * BLOCK_SIZE - residual);
if (b_needed != b_allocated) {
insert_bit(zone_map + b_allocated - 1, 0, 8 * BLOCK_SIZE);
}
insert_bit(zone_map, 0, 1); /* bit zero must always be allocated */
insert_bit(INODE_MAP, 0, 1); /* inode zero not used but must be
* allocated */
}
/* The next routine is copied from fsck.c. Modify some names for consistency.
* This sharing should be done better.
*/
#define BITMAPSHIFT BIT_MAP_SHIFT
#define bit_nr unsigned
/* Convert from bit count to a block count. The usual expression
*
* (nr_bits + (1 << BITMAPSHIFT) - 1) >> BITMAPSHIFT
*
* doesn't work because of overflow.
*
* Other overflow bugs, such as the expression for N_ILIST overflowing when
* s_inodes is just over INODES_PER_BLOCK less than the maximum+1, are not
* fixed yet, because that number of inodes is silly.
*/
int bitmapsize(nr_bits)
bit_nr nr_bits;
{
int nr_blocks;
nr_blocks = nr_bits >> BITMAPSHIFT;
if ((nr_blocks << BITMAPSHIFT) < nr_bits)
++nr_blocks;
return(nr_blocks);
}
/*================================================================
* rootdir - install the root directory
*===============================================================*/
rootdir(inode)
int inode;
{
int z;
z = alloc_zone();
add_zone(inode, z, 32L, current_time);
enter_dir(inode, ".", inode);
enter_dir(inode, "..", inode);
incr_link(inode);
incr_link(inode);
}
/*================================================================
* eat_dir - recursively install directory
*===============================================================*/
eat_dir(parent)
int parent; /* parent's inode nr */
{
/* Read prototype lines and set up directory. Recurse if need be. */
char *token[MAX_TOKENS], *p;
char line[LINE_LEN];
int mode, n, usrid, grpid, z, maj, min, f;
long size;
while (1) {
getline(line, token);
p = token[0];
if (*p == '$') return;
p = token[1];
mode = mode_con(p);
usrid = atoi(token[2]);
grpid = atoi(token[3]);
if (grpid & 0200) write(2, gwarning, 14);
n = alloc_inode(mode, usrid, grpid);
/* Enter name in directory and update directory's size. */
enter_dir(parent, token[0], n);
incr_size(parent, 16L);
/* Check to see if file is directory or special. */
incr_link(n);
if (*p == 'd') {
/* This is a directory. */
z = alloc_zone(); /* zone for new directory */
add_zone(n, z, 32L, current_time);
enter_dir(n, ".", n);
enter_dir(n, "..", parent);
incr_link(parent);
incr_link(n);
eat_dir(n);
} else if (*p == 'b' || *p == 'c') {
/* Special file. */
maj = atoi(token[4]);
min = atoi(token[5]);
size = 0;
if (token[6]) size = atoi(token[6]);
size = BLOCK_SIZE * size;
add_zone(n, (maj << 8) | min, size, current_time);
} else {
/* Regular file. Go read it. */
if ((f = open(token[4], O_RDONLY)) < 0) {
write(2, "Can't open file ", 16);
write(2, token[4], strlen(token[4]));
write(2, "\n", 1);
} else
eat_file(n, f);
}
}
}
/*================================================================
* eat_file - copy file to MINIX
*===============================================================*/
/* Zonesize >= blocksize */
eat_file(inode, f)
int inode, f;
{
int z, ct, i, j, k;
char buf[BLOCK_SIZE];
long timeval;
extern long file_time();
do {
for (i = 0, j = 0; i < zone_size; i++, j += ct) {
for (k = 0; k < BLOCK_SIZE; k++) buf[k] = 0;
if ((ct = read(f, buf, BLOCK_SIZE)) > 0) {
if (i == 0) z = alloc_zone();
put_block((z << zone_shift) + i, buf);
}
}
timeval = (dflag ? current_time : file_time(f));
if (ct) add_zone(inode, z, (long) j, timeval);
} while (ct == BLOCK_SIZE);
close(f);
}
/*================================================================
* directory & inode management assist group
*===============================================================*/
enter_dir(parent, name, child)
int parent, child; /* inode nums */
char *name;
{
/* Enter child in parent directory */
/* Works for dir > 1 block and zone > block */
int i, j, k, l, b, z, off;
char *p1, *p2;
struct { /* FIXME, DEBUG - use <sys/dir.h> */
ino_t inumb;
char name[14];
} dir_entry[NR_DIR_ENTRIES];
d_inode ino[INODES_PER_BLOCK];
b = ((parent - 1) / INODES_PER_BLOCK) + inode_offset;
off = (parent - 1) % INODES_PER_BLOCK;
get_block(b, ino);
for (k = 0; k < NR_DZONE_NUM; k++) {
z = ino[off].i_zone[k];
if (z == 0) {
z = alloc_zone();
ino[off].i_zone[k] = z;
}
for (l = 0; l < zone_size; l++) {
get_block((z << zone_shift) + l, dir_entry);
for (i = 0; i < NR_DIR_ENTRIES; i++) {
if (dir_entry[i].inumb == 0) {
dir_entry[i].inumb = child;
p1 = name;
p2 = dir_entry[i].name;
j = 14;
while (j--) {
*p2++ = *p1;
if (*p1 != 0) p1++;
}
put_block((z << zone_shift) + l, dir_entry);
put_block(b, ino);
return;
}
}
}
}
printf("Directory-inode %d beyond direct blocks. Could not enter %s\n",
parent, name);
pexit("Halt");
}
add_zone(n, z, bytes, cur_time)
int n, z;
long bytes, cur_time;
{
/* Add zone z to inode n. The file has grown by 'bytes' bytes. */
int b, off, indir, i;
zone_nr blk[NR_INDIRECTS];
d_inode *p;
d_inode inode[INODES_PER_BLOCK];
b = ((n - 1) / INODES_PER_BLOCK) + inode_offset;
off = (n - 1) % INODES_PER_BLOCK;
get_block(b, inode);
p = &inode[off];
p->i_size += bytes;
p->i_mtime = cur_time;
for (i = 0; i < NR_DZONE_NUM; i++)
if (p->i_zone[i] == 0) {
p->i_zone[i] = z;
put_block(b, inode);
return;
}
put_block(b, inode);
/* File has grown beyond a small file. */
if (p->i_zone[NR_DZONE_NUM] == 0) p->i_zone[NR_DZONE_NUM] = alloc_zone();
indir = p->i_zone[NR_DZONE_NUM];
put_block(b, inode);
b = indir << zone_shift;
get_block(b, blk);
for (i = 0; i < NR_INDIRECTS; i++)
if (blk[i] == 0) {
blk[i] = (zone_nr) z;
put_block(b, blk);
return;
}
pexit("File has grown beyond single indirect");
}
incr_link(n)
int n;
{
/* Increment the link count to inode n */
int b, off;
d_inode inode[INODES_PER_BLOCK];
b = ((n - 1) / INODES_PER_BLOCK) + inode_offset;
off = (n - 1) % INODES_PER_BLOCK;
get_block(b, inode);
inode[off].i_nlinks++;
put_block(b, inode);
}
incr_size(n, count)
int n;
long count;
{
/* Increment the file-size in inode n */
int b, off;
d_inode inode[INODES_PER_BLOCK];
b = ((n - 1) / INODES_PER_BLOCK) + inode_offset;
off = (n - 1) % INODES_PER_BLOCK;
get_block(b, inode);
inode[off].i_size += count;
put_block(b, inode);
}
/*================================================================
* allocation assist group
*===============================================================*/
int alloc_inode(mode, usrid, grpid)
int mode, usrid, grpid;
{
int num, b, off;
d_inode inode[INODES_PER_BLOCK];
num = next_inode++;
if (num >= nrinodes) pexit("File system does not have enough inodes");
b = ((num - 1) / INODES_PER_BLOCK) + inode_offset;
off = (num - 1) % INODES_PER_BLOCK;
get_block(b, inode);
inode[off].i_mode = mode;
inode[off].i_uid = usrid;
inode[off].i_gid = grpid;
put_block(b, inode);
/* Set the bit in the bit map. */
insert_bit(INODE_MAP, num, 1);
return(num);
}
int alloc_zone()
{
/* Allocate a new zone */
/* Works for zone > block */
int b, z, i;
z = next_zone++;
b = z << zone_shift;
if ((b + zone_size) > nrblocks)
pexit("File system not big enough for all the files");
for (i = 0; i < zone_size; i++)
put_block(b + i, zero); /* give an empty zone */
insert_bit(zone_map, z - zoff, 1);
return(z);
}
insert_bit(block, bit, count)
int block, bit, count;
{
/* Insert 'count' bits in the bitmap */
int w, s, i;
short buf[BLOCK_SIZE / sizeof(short)];
get_block(block, buf);
for (i = bit; i < bit + count; i++) {
w = i / (8 * sizeof(short));
s = i % (8 * sizeof(short));
buf[w] |= (1 << s);
}
put_block(block, buf);
}
/*================================================================
* proto-file processing assist group
*===============================================================*/
int mode_con(p)
char *p;
{
/* Convert string to mode */
int o1, o2, o3, mode;
char c1, c2, c3;
c1 = *p++;
c2 = *p++;
c3 = *p++;
o1 = *p++ - '0';
o2 = *p++ - '0';
o3 = *p++ - '0';
mode = (o1 << 6) | (o2 << 3) | o3;
if (c1 == 'd') mode += I_DIRECTORY;
if (c1 == 'b') mode += I_BLOCK_SPECIAL;
if (c1 == 'c') mode += I_CHAR_SPECIAL;
if (c1 == '-') mode += I_REGULAR;
if (c2 == 'u') mode += I_SET_UID_BIT;
if (c3 == 'g') mode += I_SET_GID_BIT;
return(mode);
}
getline(line, parse)
char *parse[MAX_TOKENS];
char line[LINE_LEN];
{
/* Read a line and break it up in tokens */
int k;
char c, *p;
int d;
for (k = 0; k < MAX_TOKENS; k++) parse[k] = 0;
for (k = 0; k < LINE_LEN; k++) line[k] = 0;
k = 0;
parse[0] = 0;
p = line;
while (1) {
if (++k > LINE_LEN) pexit("Line too long");
d = fgetc(proto);
if (d == EOF) pexit("Unexpected end-of-file");
*p = d;
if (*p == '\n') lct++;
if (*p == ' ' || *p == '\t') *p = 0;
if (*p == '\n') {
*p++ = 0;
*p = '\n';
break;
}
p++;
}
k = 0;
p = line;
lastp = line;
while (1) {
c = *p++;
if (c == '\n') return;
if (c == 0) continue;
parse[k++] = p - 1;
do {
c = *p++;
} while (c != 0 && c != '\n');
}
}
/*================================================================
* other stuff
*===============================================================*/
long file_time(f)
int f;
{
#ifdef UNIX
struct stat statbuf;
fstat(f, &statbuf);
return(statbuf.st_mtime);
#else /* fstat not supported by DOS */
return(0L);
#endif
}
pexit(s)
char *s;
{
char *s0;
s0 = s;
while (*s0 != 0) s0++;
write(2, "Error: ", 7);
write(2, s, (int) (s0 - s));
write(2, "\n", 1);
printf("Line %d being processed when error detected.\n", lct);
flush();
exit(2);
}
copy(from, to, count)
char *from, *to;
int count;
{
while (count--) *to++ = *from++;
}
print_fs()
{
int i, j, k;
d_inode inode[INODES_PER_BLOCK];
int ibuf[INTS_PER_BLOCK], b;
struct { /* FIXME, DEBUG - use <sys/dir.h> */
ino_t inum;
char name[14];
} dir[NR_DIR_ENTRIES];
get_block(1, ibuf);
printf("\nSuperblock: ");
for (i = 0; i < 8; i++) printf("%06o ", ibuf[i]);
get_block(2, ibuf);
printf("\nInode map: ");
for (i = 0; i < 9; i++) printf("%06o ", ibuf[i]);
get_block(3, ibuf);
printf("\nZone map: ");
for (i = 0; i < 9; i++) printf("%06o ", ibuf[i]);
printf("\n");
for (b = 4; b < 8; b++) {
get_block(b, inode);
for (i = 0; i < INODES_PER_BLOCK; i++) {
k = INODES_PER_BLOCK * (b - 4) + i + 1;
if (k > nrinodes) break;
if (inode[i].i_mode != 0) {
printf("Inode %2d: mode=", k, inode[i].i_mode);
printf("%06o", inode[i].i_mode);
printf(" uid=%2d gid=%2d size=",
inode[i].i_uid, inode[i].i_gid);
printf("%6ld", inode[i].i_size);
printf(" zone[0]=%d\n", inode[i].i_zone[0]);
}
if ((inode[i].i_mode & I_TYPE) == I_DIRECTORY) {
/* This is a directory */
get_block(inode[i].i_zone[0], dir);
for (j = 0; j < NR_DIR_ENTRIES; j++)
if (dir[j].inum)
printf("\tInode %2d: %s\n", dir[j].inum, dir[j].name);
}
}
}
printf("%d inodes used. %d zones used.\n", next_inode - 1, next_zone);
}
int read_and_set(n)
int n;
{
/* The first time a block is read, it returns alls 0s, unless there has
* been a write. This routine checks to see if a block has been accessed.
*/
int w, s, mask, r;
w = n / 8;
s = n % 8;
mask = 1 << s;
r = (umap[w] & mask ? 1 : 0);
umap[w] |= mask;
return(r);
}
/*================================================================
* get_block & put_block for MS-DOS
*===============================================================*/
#ifdef DOS
/*
* These are the get_block and put_block routines
* when compiling & running mkfs.c under MS-DOS.
*
* It requires the (asembler) routines absread & abswrite
* from the file diskio.asm. Since these routines just do
* as they are told (read & write the sector specified),
* a local cache is used to minimize the i/o-overhead for
* frequently used blocks.
*
* The global variable "file" determines whether the output
* is to a disk-device or to a binary file.
*/
#define PH_SECTSIZE 512 /* size of a physical disk-sector */
char *derrtab[14] = {
"no error",
"disk is read-only",
"unknown unit",
"device not ready",
"bad command",
"data error",
"internal error: bad request structure length",
"seek error",
"unknown media type",
"sector not found",
"printer out of paper (??)",
"write fault",
"read error",
"general error"
};
#define CACHE_SIZE 20 /* 20 block-buffers */
struct cache {
char blockbuf[BLOCK_SIZE];
int blocknum;
int dirty;
int usecnt;
} cache[CACHE_SIZE];
special(string)
char *string;
{
if (string[1] == ':' && string[2] == 0) {
/* Format: d: or d:fname */
disk = (string[0] & ~32) - 'A';
if (disk > 1 && !override) /* safety precaution */
pexit("Bad drive specifier for special");
} else {
file = 1;
if ((fd = creat(string, BWRITE)) == 0)
pexit("Can't open special file");
}
}
get_block(n, buf)
int n;
char buf[BLOCK_SIZE];
{
/* Get a block to the user */
struct cache *bp, *fp;
/* First access returns a zero block */
if (read_and_set(n) == 0) {
copy(zero, buf, BLOCK_SIZE);
return;
}
/* Look for block in cache */
fp = 0;
for (bp = cache; bp < &cache[CACHE_SIZE]; bp++) {
if (bp->blocknum == n) {
copy(bp, buf, BLOCK_SIZE);
bp->usecnt++;
return;
}
/* Remember clean block */
if (bp->dirty == 0)
if (fp) {
if (fp->usecnt > bp->usecnt) fp = bp;
} else
fp = bp;
}
/* Block not in cache, get it */
if (!fp) {
/* No clean buf, flush one */
for (bp = cache, fp = cache; bp < &cache[CACHE_SIZE]; bp++)
if (fp->usecnt > bp->usecnt) fp = bp;
mx_write(fp->blocknum, fp);
}
mx_read(n, fp);
fp->dirty = 0;
fp->usecnt = 0;
fp->blocknum = n;
copy(fp, buf, BLOCK_SIZE);
}
put_block(n, buf)
int n;
char buf[BLOCK_SIZE];
{
/* Accept block from user */
struct cache *fp, *bp;
read_and_set(n);
/* Look for block in cache */
fp = 0;
for (bp = cache; bp < &cache[CACHE_SIZE]; bp++) {
if (bp->blocknum == n) {
copy(buf, bp, BLOCK_SIZE);
bp->dirty = 1;
return;
}
/* Remember clean block */
if (bp->dirty == 0)
if (fp) {
if (fp->usecnt > bp->usecnt) fp = bp;
} else
fp = bp;
}
/* Block not in cache */
if (!fp) {
/* No clean buf, flush one */
for (bp = cache, fp = cache; bp < &cache[CACHE_SIZE]; bp++)
if (fp->usecnt > bp->usecnt) fp = bp;
mx_write(fp->blocknum, fp);
}
fp->dirty = 1;
fp->usecnt = 1;
fp->blocknum = n;
copy(buf, fp, BLOCK_SIZE);
}
cache_init()
{
struct cache *bp;
for (bp = cache; bp < &cache[CACHE_SIZE]; bp++) bp->blocknum = -1;
}
flush()
{
/* Flush all dirty blocks to disk */
struct cache *bp;
for (bp = cache; bp < &cache[CACHE_SIZE]; bp++)
if (bp->dirty) {
mx_write(bp->blocknum, bp);
bp->dirty = 0;
}
}
/*==================================================================
* hard read & write etc.
*=================================================================*/
#define MAX_RETRIES 5
mx_read(blocknr, buf)
int blocknr;
char buf[BLOCK_SIZE];
{
/* Read the requested MINIX-block in core */
char (*bp)[PH_SECTSIZE];
int sectnum, retries, err;
if (file) {
lseek(fd, (long) blocknr * BLOCK_SIZE, 0);
if (read(fd, buf, BLOCK_SIZE) != BLOCK_SIZE)
pexit("mx_read: error reading file");
} else {
sectnum = blocknr * (BLOCK_SIZE / PH_SECTSIZE);
for (bp = buf; bp < &buf[BLOCK_SIZE]; bp++) {
retries = MAX_RETRIES;
do
err = absread(disk, sectnum, bp);
while (err && --retries);
if (retries) {
sectnum++;
} else {
dexit("mx_read", sectnum, err);
}
}
}
}
mx_write(blocknr, buf)
int blocknr;
char buf[BLOCK_SIZE];
{
/* Write the MINIX-block to disk */
char (*bp)[PH_SECTSIZE];
int retries, sectnum, err;
if (file) {
lseek(fd, blocknr * BLOCK_SIZE, 0);
if (write(fd, buf, BLOCK_SIZE) != BLOCK_SIZE) {
pexit("mx_write: error writing file");
}
} else {
sectnum = blocknr * (BLOCK_SIZE / PH_SECTSIZE);
for (bp = buf; bp < &buf[BLOCK_SIZE]; bp++) {
retries = MAX_RETRIES;
do {
err = abswrite(disk, sectnum, bp);
} while (err && --retries);
if (retries) {
sectnum++;
} else {
dexit("mx_write", sectnum, err);
}
}
}
}
dexit(s, sectnum, err)
int sectnum, err;
char *s;
{
printf("Error: %s, sector: %d, code: %d, meaning: %s\n",
s, sectnum, err, derrtab[err]);
exit(2);
}
#endif
/*================================================================
* get_block & put_block for UNIX
*===============================================================*/
#ifdef UNIX
special(string)
char *string;
{
fd = creat(string, 0777);
close(fd);
fd = open(string, O_RDWR);
if (fd < 0) pexit("Can't open special file");
#if (MACHINE == ATARI)
{
struct stat statbuf;
if (fstat(fd, &statbuf) < 0)
return;
isdev = (statbuf.st_mode & S_IFMT) == S_IFCHR
||
(statbuf.st_mode & S_IFMT) == S_IFBLK
;
}
#endif
}
get_block(n, buf)
int n;
char buf[BLOCK_SIZE];
{
/* Read a block. */
int k;
/* First access returns a zero block */
if (read_and_set(n) == 0) {
copy(zero, buf, BLOCK_SIZE);
return;
}
lseek(fd, (long) n * BLOCK_SIZE, SEEK_SET);
k = read(fd, buf, BLOCK_SIZE);
if (k != BLOCK_SIZE) {
pexit("get_block couldn't read");
}
}
put_block(n, buf)
int n;
char buf[BLOCK_SIZE];
{
/* Write a block. */
read_and_set(n);
if (lseek(fd, (long) n * BLOCK_SIZE, SEEK_SET) < 0L) {
pexit("put_block couldn't seek");
}
if (write(fd, buf, BLOCK_SIZE) != BLOCK_SIZE) {
pexit("put_block couldn't write");
}
}
/* Dummy routines to keep source file clean from #ifdefs */
flush()
{
return;
}
cache_init()
{
return;
}
#endif