2 * e2label.c - Print or change the volume label on an ext2 fs
4 * Written by Andries Brouwer (aeb@cwi.nl), 970714
6 * Copyright 1997, 1998 by Theodore Ts'o.
9 * This file may be redistributed under the terms of the GNU Public
35 #include "nls-enable.h"
37 #define EXT2_SUPER_MAGIC 0xEF53
41 struct ext2_super_block {
43 unsigned char s_magic[2];
45 char s_volume_name[VOLNAMSZ];
46 char s_last_mounted[64];
50 static int open_e2fs (char *dev, int mode)
57 fprintf (stderr, _("e2label: cannot open %s\n"), dev);
60 if (lseek(fd, 1024, SEEK_SET) != 1024) {
62 fprintf (stderr, _("e2label: cannot seek to superblock\n"));
65 if (read(fd, (char *) &sb, sizeof(sb)) != sizeof(sb)) {
67 fprintf (stderr, _("e2label: error reading superblock\n"));
70 if (sb.s_magic[0] + 256*sb.s_magic[1] != EXT2_SUPER_MAGIC) {
71 fprintf (stderr, _("e2label: not an ext2 filesystem\n"));
78 static void print_label (char *dev)
80 char label[VOLNAMSZ+1];
82 open_e2fs (dev, O_RDONLY);
83 strncpy(label, sb.s_volume_name, VOLNAMSZ);
85 printf("%s\n", label);
88 static void change_label (char *dev, char *label)
92 fd = open_e2fs(dev, O_RDWR);
93 memset(sb.s_volume_name, 0, VOLNAMSZ);
94 strncpy(sb.s_volume_name, label, VOLNAMSZ);
95 if (strlen(label) > VOLNAMSZ)
96 fprintf(stderr, _("Warning: label too long, truncating.\n"));
97 if (lseek(fd, 1024, SEEK_SET) != 1024) {
99 fprintf (stderr, _("e2label: cannot seek to superblock again\n"));
102 if (write(fd, (char *) &sb, sizeof(sb)) != sizeof(sb)) {
104 fprintf (stderr, _("e2label: error writing superblock\n"));
109 int main (int argc, char ** argv)
112 print_label(argv[1]);
114 change_label(argv[1], argv[2]);
116 fprintf(stderr, _("Usage: e2label device [newlabel]\n"));