isosize.c

Util-linux 软件包包含许多工具。其中比较重要的是加载、卸载、格式化、分区和管理硬盘驱动器

/*
 * isosize.c - Andries Brouwer, 000608
 *
 * use header info to find size of iso9660 file system
 * output a number - useful in scripts
 *
 * Synopsis:
 *    isosize [-x] [-d <num>] <filename>
 *        where "-x" gives length in sectors and sector size while
 *              without this argument the size is given in bytes
 *        without "-x" gives length in bytes unless "-d <num>" is
 *		given. In the latter case the length in bytes divided
 *		by <num> is given
 *
 *  Version 2.03 2000/12/21
 *     - add "-d <num>" option and use long long to fix things > 2 GB
 *  Version 2.02 2000/10/11
 *     - error messages on IO failures [D. Gilbert]
 *
 */
#include <stdio.h>
#include <stdlib.h>
#include <getopt.h>
#include <fcntl.h>
#include <unistd.h>
#include <string.h>

#include "nls.h"

#define ISODCL(from, to) (to - from + 1)

int xflag;

static int
isonum_721 (unsigned char * p) {
        return ((p[0] & 0xff)
                | ((p[1] & 0xff) << 8));
}

static int
isonum_722 (unsigned char * p) {
        return ((p[1] & 0xff)
                | ((p[0] & 0xff) << 8));
}

static int
isonum_723 (unsigned char * p) {
        int le = isonum_721 (p);
        int be = isonum_722 (p+2);
        if (xflag && le != be)
		/* translation is useless */
                fprintf(stderr, "723error: le=%d be=%d\n", le, be);
        return (le);
}

static int
isonum_731 (unsigned char * p) {
    return ((p[0] & 0xff)
            | ((p[1] & 0xff) << 8)
            | ((p[2] & 0xff) << 16)
            | ((p[3] & 0xff) << 24));
}

static int
isonum_732 (unsigned char * p) {
    return ((p[3] & 0xff)
            | ((p[2] & 0xff) << 8)
            | ((p[1] & 0xff) << 16)
            | ((p[0] & 0xff) << 24));
}


static int
isonum_733 (unsigned char * p) {
    int le = isonum_731 (p);
    int be = isonum_732 (p+4);
    if (xflag && le != be)
	    /* translation is useless */
            fprintf(stderr, "733error: le=%d be=%d\n", le, be);
    return (le);
}

struct iso_primary_descriptor {
    unsigned char type                      [ISODCL (  1,   1)]; /* 711 */
    unsigned char id                        [ISODCL (  2,   6)];
    unsigned char version                   [ISODCL (  7,   7)]; /* 711 */
    unsigned char unused1                   [ISODCL (  8,   8)];
    unsigned char system_id                 [ISODCL (  9,  40)]; /* auchars */
    unsigned char volume_id                 [ISODCL ( 41,  72)]; /* duchars */
    unsigned char unused2                   [ISODCL ( 73,  80)];
    unsigned char volume_space_size         [ISODCL ( 81,  88)]; /* 733 */
    unsigned char unused3                   [ISODCL ( 89, 120)];
    unsigned char volume_set_size           [ISODCL (121, 124)]; /* 723 */
    unsigned char volume_sequence_number    [ISODCL (125, 128)]; /* 723 */
    unsigned char logical_block_size        [ISODCL (129, 132)]; /* 723 */
    unsigned char path_table_size           [ISODCL (133, 140)]; /* 733 */
    unsigned char type_l_path_table         [ISODCL (141, 144)]; /* 731 */
    unsigned char opt_type_l_path_table     [ISODCL (145, 148)]; /* 731 */
    unsigned char type_m_path_table         [ISODCL (149, 152)]; /* 732 */
    unsigned char opt_type_m_path_table     [ISODCL (153, 156)]; /* 732 */
    unsigned char root_directory_record     [ISODCL (157, 190)]; /* 9.1 */
    unsigned char volume_set_id             [ISODCL (191, 318)]; /* duchars */
    unsigned char publisher_id              [ISODCL (319, 446)]; /* achars */
    unsigned char preparer_id               [ISODCL (447, 574)]; /* achars */
    unsigned char application_id            [ISODCL (575, 702)]; /* achars */
    unsigned char copyright_file_id         [ISODCL (703, 739)]; /* 7.5 dchars */
    unsigned char abstract_file_id          [ISODCL (740, 776)]; /* 7.5 dchars */
    unsigned char bibliographic_file_id     [ISODCL (777, 813)]; /* 7.5 dchars */
    unsigned char creation_date             [ISODCL (814, 830)]; /* 8.4.26.1 */
    unsigned char modification_date         [ISODCL (831, 847)]; /* 8.4.26.1 */
    unsigned char expiration_date           [ISODCL (848, 864)]; /* 8.4.26.1 */
    unsigned char effective_date            [ISODCL (865, 881)]; /* 8.4.26.1 */
    unsigned char file_structure_version    [ISODCL (882, 882)]; /* 711 */
    unsigned char unused4                   [ISODCL (883, 883)];
    unsigned char application_data          [ISODCL (884, 1395)];
    unsigned char unused5                   [ISODCL (1396, 2048)];
};

const char *progname;
int divisor = 0;

static void
isosize(char *filenamep) {
	int fd, nsecs, ssize;
	struct iso_primary_descriptor ipd;

	if ((fd = open(filenamep, O_RDONLY)) < 0) {
		perror(filenamep);
		fprintf(stderr, _("%s: failed to open: %s\n"),
			progname, filenamep);
		exit(1);
	}
	if (lseek(fd, 16 << 11, 0) == (off_t)-1) {
		perror("lseek");
		fprintf(stderr, _("%s: seek error on %s\n"),
			progname, filenamep);
		exit(1);
	}
	if (read(fd, &ipd, sizeof(ipd)) < 0) {
		perror("read");
		fprintf(stderr, _("%s: read error on %s\n"),
			progname, filenamep);
		exit(1);
	}

	nsecs = isonum_733(ipd.volume_space_size);
	ssize = isonum_723(ipd.logical_block_size); /* nowadays always 2048 */

	if (xflag) {
		printf (_("sector count: %d, sector size: %d\n"),
			nsecs, ssize);
	} else {
		long long product = nsecs;

		if (divisor == 0)
			printf ("%lld\n", product * ssize);
		else if (divisor == ssize)
			printf ("%d\n", nsecs);
		else
			printf ("%lld\n", (product * ssize) / divisor);
	}
}

int
main(int argc, char * argv[]) {
	int j, ct;
	char *p;

	progname = argv[0];
	if ((p = strrchr(progname, '/')) != NULL)
		progname = p+1;

	setlocale(LC_ALL, "");
	bindtextdomain(PACKAGE, LOCALEDIR);
	textdomain(PACKAGE);

	if (argc >= 2 &&
	    (!strcmp(argv[1], "-V") || !strcmp(argv[1], "--version"))) {
		printf(_("%s from %s\n"), progname, util_linux_version);
		exit(0);
	}

	for (;;) {
		int opt;

		opt = getopt(argc, argv, "xd:");
		if (opt == -1)
			break;
		switch (opt) {
		case 'd':
			divisor = atoi(optarg);
			break;
		case 'x':
			xflag = 1;
			break;
		default:
			fprintf(stderr,
				_("%s: option parse error\n"), progname);
			exit(1);
		}
	}

	ct = argc - optind;

	if (ct <= 0) {
		fprintf(stderr, _("Usage: %s [-x] [-d <num>] iso9660-image\n"),
			progname);
		exit(1);
	}

	for (j = optind; j < argc; j++) {
		if (ct > 1)
			printf("%s: ", argv[j]);
		isosize(argv[j]);
	}

	return 0;
}