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/*
* e2label.c - Print or change the volume label on an ext2 fs
*
* Written by Andries Brouwer (aeb@cwi.nl), 970714
*
* Copyright 1997, 1998 by Theodore Ts'o.
*
* %Begin-Header%
* This file may be redistributed under the terms of the GNU Public
* License.
* %End-Header%
*/
#include "config.h"
#include <stdio.h>
#include <string.h>
#include <fcntl.h>
#include <ctype.h>
#include <termios.h>
#include <time.h>
#ifdef HAVE_GETOPT_H
#include <getopt.h>
#else
extern char *optarg;
extern int optind;
#endif
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif
#ifdef HAVE_STDLIB_H
#include <stdlib.h>
#endif
#ifdef HAVE_ERRNO_H
#include <errno.h>
#endif
#include "support/nls-enable.h"
#define EXT2_SUPER_MAGIC 0xEF53
#define VOLNAMSZ 16
struct ext2_super_block {
char s_dummy0[56];
unsigned char s_magic[2];
char s_dummy1[62];
char s_volume_name[VOLNAMSZ];
char s_last_mounted[64];
char s_dummy2[824];
} sb;
static int open_e2fs (char *dev, int mode)
{
int fd;
fd = open(dev, mode);
if (fd < 0) {
perror(dev);
fprintf (stderr, _("e2label: cannot open %s\n"), dev);
exit(1);
}
if (lseek(fd, 1024, SEEK_SET) != 1024) {
perror(dev);
fprintf (stderr, _("e2label: cannot seek to superblock\n"));
exit(1);
}
if (read(fd, (char *) &sb, sizeof(sb)) != sizeof(sb)) {
perror(dev);
fprintf (stderr, _("e2label: error reading superblock\n"));
exit(1);
}
if (sb.s_magic[0] + 256*sb.s_magic[1] != EXT2_SUPER_MAGIC) {
fprintf (stderr, _("e2label: not an ext2 filesystem\n"));
exit(1);
}
return fd;
}
static void print_label (char *dev)
{
char label[VOLNAMSZ+1];
open_e2fs (dev, O_RDONLY);
snprintf(label, sizeof(label), "%.*s", EXT2_LEN_STR(sb.s_volume_name));
label[VOLNAMSZ] = 0;
printf("%s\n", label);
}
static void change_label (char *dev, char *label)
{
int fd;
fd = open_e2fs(dev, O_RDWR);
memset(sb.s_volume_name, 0, VOLNAMSZ);
strncpy(sb.s_volume_name, label, VOLNAMSZ);
if (strlen(label) > VOLNAMSZ)
fprintf(stderr, _("Warning: label too long, truncating.\n"));
if (lseek(fd, 1024, SEEK_SET) != 1024) {
perror(dev);
fprintf (stderr, _("e2label: cannot seek to superblock again\n"));
exit(1);
}
if (write(fd, (char *) &sb, sizeof(sb)) != sizeof(sb)) {
perror(dev);
fprintf (stderr, _("e2label: error writing superblock\n"));
exit(1);
}
}
int main (int argc, char ** argv)
{
if (argc == 2)
print_label(argv[1]);
else if (argc == 3)
change_label(argv[1], argv[2]);
else {
fprintf(stderr, _("Usage: e2label device [newlabel]\n"));
exit(1);
}
return 0;
}
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