qubes-installer-qubes-os/anaconda/isys/isofs.c

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/*
* isofs.c
*
* Copyright (C) 2007 Red Hat, Inc. All rights reserved.
*
* 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, see <http://www.gnu.org/licenses/>.
*/
#include <fcntl.h>
#include <string.h>
#include <unistd.h>
#define BLOCK_SIZE 2048
/* returns 1 if file is an ISO, 0 otherwise */
int fileIsIso(const char * file) {
int blkNum;
char magic[5];
int fd;
fd = open(file, O_RDONLY);
if (fd < 0)
return 0;
for (blkNum = 16; blkNum < 100; blkNum++) {
if (lseek(fd, blkNum * BLOCK_SIZE + 1, SEEK_SET) < 0) {
close(fd);
return 0;
}
if (read(fd, magic, sizeof(magic)) != sizeof(magic)) {
close(fd);
return 0;
}
if (!strncmp(magic, "CD001", 5)) {
close(fd);
return 1;
}
}
close(fd);
return 0;
}