openfiles.c

使用libscsi做的一系列cdrom操作工具程序。包含cdwrite,cdflush,cdda三个程序

/*
  openfiles -- open track files and calculate space needed
  Copyright (C) 1996 Dieter Baron and Armin Obersteiner

  This file is part of cdwrite.
  The authors can be contacted at
	<[e-mail]>
	<[e-mail]>

  This program is free software; you can redistribute it and/or modify
  it under the terms of the GNU General Public License as published by
  the Free Software Foundation; either version 2 of the License, or
  (at your option) any later version.

  This program is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  GNU General Public License for more details.

  You should have received a copy of the GNU General Public License
  along with this program; if not, write to the Free Software
  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/

#include "cdwrite.h"

#include <sys/types.h>
#include <sys/stat.h>
#include <stdio.h>
#include <string.h>
#include <limits.h>
#include <unistd.h>
#include <errno.h>
#include <fcntl.h>



int
open_files(void)
{
    int i;
    u_char b[2048];
    int blks, blksize;
    struct stat stat;

    blks = 0;

    for (i=0; i<track; i++) {
	if (strcmp(tinfo[i].name, "-") == 0)
	    tinfo[i].fd = 0;
	else {
	    if ((tinfo[i].fd = open(tinfo[i].name, O_RDONLY, 0)) < 0) {
		fprintf(stderr, "%s: can't open `%s': %s\n",
			prg, tinfo[i].name, strerror(errno));
		return -1;
	    }
	}

	if (tinfo[i].size == ULONG_MAX) {
	    if (lseek(tinfo[i].fd, 16<<11, SEEK_SET) < 0) {
		fprintf(stderr, "%s: can't get iso size for `%s' "
			"(seek): %s\n",
			prg, tinfo[i].name, strerror(errno));
		return -1;
	    }
	    if (read(tinfo[i].fd, b, 2048) < 0) {
		fprintf(stderr, "%s: can't get iso size for `%s' (read): %s\n",
			prg, tinfo[i].name, strerror(errno));
		return -1;
	    }
	    
	    if (lseek(tinfo[i].fd, 0, SEEK_SET) < 0) {
		fprintf(stderr, "%s: can't rewind `%s': %s\n",
			prg, tinfo[i].name, strerror(errno));
		return -1;
	    }

#if SC_BIGENDIAN
	    tinfo[i].size = *(u_long *)(b+84)*2048;
#else
	    tinfo[i].size = *(u_long *)(b+80)*2048;
#endif
	    if (tinfo[i].size == 0) {
		fprintf(stderr, "%s: iso size for `%s' is zero\n",
			prg, tinfo[i].name);
		return -1;
	    }
	}
    
	if (fstat(tinfo[i].fd, &stat) < 0) {
	    fprintf(stderr, "%s: can't stat `%s': %s\n",
		    prg, tinfo[i].name, strerror(errno));
	    return -1;
	}

	if (tinfo[i].size == 0) {
#if defined(S_IFCHR) && defined(S_IFBLK)
	    if ((stat.st_mode & S_IFMT) == S_IFCHR
		|| (stat.st_mode & S_IFMT) == S_IFBLK) {
		fprintf(stderr, "%s: `%s' is special device, but no "
			"size specified\n",
			prg, tinfo[i].name);
		return -1;
	    }
#endif
        
	    if ((tinfo[i].size=(u_long)stat.st_size) == 0
		&& verbose > -1) {
		fprintf(stderr, "%s: warning: unknown size for "
			"track %d (%s)\n",
			prg, i, tinfo[i].name);
		if (confirm > -1)
		    confirm = 1;
	    }
	}
	else {
	    if (tinfo[i].size > stat.st_size && stat.st_size != 0) {
		fprintf(stderr, "%s: `%s': specified size (%ld) is larger "
			"than actual (%ld)\n",
			prg, tinfo[i].name,
			(long)tinfo[i].size, (long)stat.st_size);
		return -1;
	    }
	}
    
	blksize = tinfo[i].audio ? 2352 : 2048;

	if (tinfo[i].size % blksize != 0 && verbose > -1) {
	    fprintf(stderr, "%s: warning: length of track %d (%s) is not "
		    "multiple of block length\n",
		    prg, i, tinfo[i].name);
	    if (confirm > -1)
		confirm = 1;
	}
	blks += (tinfo[i].size+blksize-1) / blksize;
    }

    return blks;
}