minix/commands/vol/vol.c

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2005-04-21 16:53:53 +02:00
/* vol - break stdin into volumes Author: Andy Tanenbaum */
/* This program reads standard input and writes it onto diskettes, pausing
* at the start of each one. It's main use is for saving files that are
* larger than a single diskette. Vol just writes its standard input onto
* a diskette, and prompts for a new one when it is full. This mechanism
* is transparent to the process producing vol's standard input. For example,
* tar cf - . | vol -w 360 /dev/fd0
* puts the tar output as as many diskettes as needed. To read them back in,
* use
* vol -r 360 /dev/fd0 | tar xf -
*
* Changed 17 Nov 1993 by Kees J. Bot to handle buffering to slow devices.
* Changed 27 Jul 1994 by Kees J. Bot to auto discover data direction + -rw.
* Changed 19 Sep 1995 by Kees J. Bot to do better buffering to tapes.
*/
#include <sys/types.h>
#include <fcntl.h>
#include <sys/stat.h>
#include <errno.h>
#include <stdlib.h>
#include <unistd.h>
#include <stdio.h>
#include <limits.h>
#include <string.h>
#include <sys/ioctl.h>
#include <sys/mtio.h>
#include <minix/partition.h>
/* Preferred block size to variable block length tapes, block devices or files.
*/
#define VAR_BLKSIZ 8192
/* Required block size multiple of fixed block size tapes (usually updated by
* 'mt status' data) and character devices.
*/
#define FIX_BLKSIZ 512
/* Maximum multiple block size. */
#if __minix_vmd
#define MULT_MAX 1048576
#else
#define MULT_MAX ((ssize_t) (SSIZE_MAX < 65536L ? SSIZE_MAX : 65536L))
#endif
char *buffer = NULL;
size_t block_size = 0, mult_max = 0;
size_t buffer_size;
u64_t volume_size;
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char *str_vol_size;
int rflag = 0, wflag = 0, oneflag = 0, variable = 0;
int main(int argc, char **argv);
void usage(void);
long str2size(char *name, char *str, long min, long max, int assume_kb);
void tape_inquire(char *name, int fd);
void allocate_buffer(void);
void diskio(int fd1, int fd2, char *file1, char *file2);
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int main(argc, argv)
int argc;
char *argv[];
{
int volume = 1, fd, tty, i, init, autovolsize;
char *p, *name;
struct stat stb;
struct part_geom part;
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char key;
/* Fetch and verify the arguments. */
i = 1;
while (i < argc && argv[i][0] == '-') {
p = argv[i++] + 1;
if (p[0] == '-' && p[1] == 0) {
/* -- */
i++;
break;
}
while (*p != '\0') {
switch (*p++) {
case 'r':
case 'u':
rflag = 1;
break;
case 'w':
wflag = 1;
break;
case '1':
oneflag = 1;
break;
case 'b':
if (*p == 0) {
if (i == argc) usage();
p = argv[i++];
}
block_size = str2size("block", p,
1L, (long) SSIZE_MAX, 0);
p= "";
break;
case 'm':
if (*p == 0) {
if (i == argc) usage();
p = argv[i++];
}
mult_max = str2size("maximum", p,
1L, (long) SSIZE_MAX, 0);
p= "";
break;
default:
usage();
}
}
}
if (i < argc - 1) {
str_vol_size = argv[i++];
volume_size = str2size("volume", str_vol_size, 1L, LONG_MAX, 1);
autovolsize = 0;
} else {
volume_size = 0; /* unlimited (long tape) or use DIOCGETP */
autovolsize = 1;
}
if (i >= argc) usage();
name = argv[i];
if (!rflag && !wflag) {
/* Auto direction. If there is a terminal at one side then data is
* to go out at the other side.
*/
if (isatty(0)) rflag = 1;
if (isatty(1)) wflag = 1;
}
if (rflag == wflag) {
fprintf(stderr, "vol: should %s be read or written?\n", name);
usage();
}
if (stat(name, &stb) < 0) {
fprintf(stderr, "vol: %s: %s\n", name, strerror(errno));
exit(1);
}
if (!S_ISBLK(stb.st_mode) && !S_ISCHR(stb.st_mode)) {
fprintf(stderr, "vol: %s is not a device\n", name);
exit(1);
}
variable = !S_ISCHR(stb.st_mode);
if (!oneflag) {
tty = open("/dev/tty", O_RDONLY);
if (tty < 0) {
fprintf(stderr, "vol: cannot open /dev/tty\n");
exit(1);
}
}
/* Buffer initializations are yet to be done. */
init = 0;
while (1) {
sleep(1);
if (oneflag) {
if (volume != 1) {
if (rflag) exit(0);
fprintf(stderr,
"vol: can't continue, volume is full\n");
exit(1);
}
} else {
fprintf(stderr,
"\007Please insert %sput volume %d and hit return\n",
rflag ? "in" : "out", volume);
while (read(tty, &key, sizeof(key)) == 1 && key != '\n') {}
}
/* Open the special file. */
fd = open(name, rflag ? O_RDONLY : O_WRONLY);
if (fd < 0) {
fprintf(stderr, "vol: %s: %s\n", name, strerror(errno));
exit(1);
}
if (!init) {
/* Ask for the tape block size and allocate a buffer. */
if (S_ISCHR(stb.st_mode)) tape_inquire(name, fd);
allocate_buffer();
init = 1;
}
if (autovolsize) {
/* Ask the driver how big the volume is. */
if (ioctl(fd, DIOCGETP, &part) < 0) {
autovolsize = 0;
} else {
volume_size = part.size;
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}
}
/* Read or write the requisite number of blocks. */
if (rflag) {
diskio(fd, 1, name, "stdout"); /* vol -r | tar xf - */
} else {
diskio(0, fd, "stdin", name); /* tar cf - | vol -w */
}
close(fd);
volume++;
}
}
void usage()
{
fprintf(stderr,
"Usage: vol [-rw1] [-b blocksize] [-m max] [size] block-special\n");
exit(1);
}
long str2size(name, str, min, max, assume_kb)
char *name;
char *str;
long min, max;
int assume_kb;
{
/* Convert a string to a size. The number may be followed by 'm', 'k', 'b'
* or 'w' to multiply the size as shown below. If 'assume_kb' is set then
* kilobytes is the default.
*/
long size, factor;
char *ptr;
int bad;
errno = 0;
size = strtol(str, &ptr, 10);
bad = (errno != 0 || ptr == str || size < min || size > max);
if (*ptr == 0 && assume_kb) ptr = "k";
while (!bad && *ptr != 0) {
switch (*ptr++) {
case 'm':
case 'M':
factor = 1024*1024L; break;
case 'k':
case 'K':
factor = 1024; break;
case 'b':
case 'B':
factor = 512; break;
case 'w':
case 'W':
factor = 2; break;
default:
factor = 1; bad = 1;
}
if (size <= max / factor) size *= factor; else bad = 1;
}
if (bad) {
fprintf(stderr, "vol: bad %s size '%s'\n", name, str);
exit(1);
}
return size;
}
void tape_inquire(name, fd)
char *name;
int fd;
{
/* If the device happens to be a tape, then what is its block size? */
struct mtget mtget;
if (ioctl(fd, MTIOCGET, &mtget) < 0) {
if (errno != ENOTTY) {
fprintf(stderr, "vol: %s: %s\n", name,
strerror(errno));
exit(1);
}
} else {
if (mtget.mt_blksiz > SSIZE_MAX) {
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fprintf(stderr,
"vol: %s: tape block size (%lu) is too large to handle\n",
name, (unsigned long) mtget.mt_blksiz);
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exit(1);
}
if (mtget.mt_blksiz == 0) {
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variable = 1;
} else {
/* fixed */
block_size = mtget.mt_blksiz;
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}
}
}
void allocate_buffer()
{
/* Set block size and maximum multiple. */
if (block_size == 0) block_size = variable ? 1 : FIX_BLKSIZ;
if (mult_max == 0) mult_max = variable ? VAR_BLKSIZ : MULT_MAX;
/* Stretch the buffer size to the max. */
buffer_size = mult_max / block_size * block_size;
if (buffer_size == 0) buffer_size = block_size;
if (volume_size % block_size != 0) {
fprintf(stderr,
"vol: volume size (%s) is not a multiple of the block size (%lu)\n",
str_vol_size, (unsigned long) block_size);
exit(1);
}
buffer = (char *) malloc(buffer_size);
if (buffer == NULL) {
fprintf(stderr, "vol: cannot allocate a %luk buffer\n",
(unsigned long) buffer_size / 1024);
exit(1);
}
}
void diskio(fd1, fd2, file1, file2)
int fd1, fd2;
char *file1, *file2;
{
/* Read 'volume_size' bytes from 'fd1' and write them on 'fd2'. Watch out for
* the fact that reads on pipes can return less than the desired data.
*/
ssize_t n, in_needed, in_count, out_count;
long needed = volume_size;
int eof = 0;
for (;;) {
if (volume_size == 0) needed = buffer_size;
if (needed == 0) break;
in_count = 0;
in_needed = needed > buffer_size ? buffer_size : needed;
while (in_count < in_needed) {
n = in_needed - in_count;
n = eof ? 0 : read(fd1, buffer + in_count, n);
if (n == 0) {
eof = 1;
if ((n = in_count % block_size) > 0) {
n = block_size - n;
memset(buffer + in_count, '\0', n);
if ((in_count += n) > in_needed)
in_count = in_needed;
}
break;
}
if (n < 0) {
fprintf(stderr, "vol: %s: %s\n",
file1, strerror(errno));
exit(1);
}
in_count += n;
}
if (in_count == 0) exit(0); /* EOF */
out_count = 0;
while (out_count < in_count) {
n = in_count - out_count;
n = write(fd2, buffer + out_count, n);
if (n < 0) {
fprintf(stderr, "vol: %s: %s\n",
file2, strerror(errno));
exit(1);
}
out_count += n;
}
needed -= in_count;
}
}