1 /* 2 * e2label.c - Print or change the volume label on an ext2 fs 3 * 4 * Written by Andries Brouwer (aeb (at) cwi.nl), 970714 5 * 6 * Copyright 1997, 1998 by Theodore Ts'o. 7 * 8 * %Begin-Header% 9 * This file may be redistributed under the terms of the GNU Public 10 * License. 11 * %End-Header% 12 */ 13 14 #include <stdio.h> 15 #include <string.h> 16 #include <fcntl.h> 17 #include <ctype.h> 18 #include <termios.h> 19 #include <time.h> 20 #ifdef HAVE_GETOPT_H 21 #include <getopt.h> 22 #else 23 extern char *optarg; 24 extern int optind; 25 #endif 26 #ifdef HAVE_UNISTD_H 27 #include <unistd.h> 28 #endif 29 #ifdef HAVE_STDLIB_H 30 #include <stdlib.h> 31 #endif 32 #ifdef HAVE_ERRNO_H 33 #include <errno.h> 34 #endif 35 #include "nls-enable.h" 36 37 #define EXT2_SUPER_MAGIC 0xEF53 38 39 #define VOLNAMSZ 16 40 41 struct ext2_super_block { 42 char s_dummy0[56]; 43 unsigned char s_magic[2]; 44 char s_dummy1[62]; 45 char s_volume_name[VOLNAMSZ]; 46 char s_last_mounted[64]; 47 char s_dummy2[824]; 48 } sb; 49 50 static int open_e2fs (char *dev, int mode) 51 { 52 int fd; 53 54 fd = open(dev, mode); 55 if (fd < 0) { 56 perror(dev); 57 fprintf (stderr, _("e2label: cannot open %s\n"), dev); 58 exit(1); 59 } 60 if (lseek(fd, 1024, SEEK_SET) != 1024) { 61 perror(dev); 62 fprintf (stderr, _("e2label: cannot seek to superblock\n")); 63 exit(1); 64 } 65 if (read(fd, (char *) &sb, sizeof(sb)) != sizeof(sb)) { 66 perror(dev); 67 fprintf (stderr, _("e2label: error reading superblock\n")); 68 exit(1); 69 } 70 if (sb.s_magic[0] + 256*sb.s_magic[1] != EXT2_SUPER_MAGIC) { 71 fprintf (stderr, _("e2label: not an ext2 filesystem\n")); 72 exit(1); 73 } 74 75 return fd; 76 } 77 78 static void print_label (char *dev) 79 { 80 char label[VOLNAMSZ+1]; 81 82 open_e2fs (dev, O_RDONLY); 83 strncpy(label, sb.s_volume_name, VOLNAMSZ); 84 label[VOLNAMSZ] = 0; 85 printf("%s\n", label); 86 } 87 88 static void change_label (char *dev, char *label) 89 { 90 int fd; 91 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) { 98 perror(dev); 99 fprintf (stderr, _("e2label: cannot seek to superblock again\n")); 100 exit(1); 101 } 102 if (write(fd, (char *) &sb, sizeof(sb)) != sizeof(sb)) { 103 perror(dev); 104 fprintf (stderr, _("e2label: error writing superblock\n")); 105 exit(1); 106 } 107 } 108 109 int main (int argc, char ** argv) 110 { 111 if (argc == 2) 112 print_label(argv[1]); 113 else if (argc == 3) 114 change_label(argv[1], argv[2]); 115 else { 116 fprintf(stderr, _("Usage: e2label device [newlabel]\n")); 117 exit(1); 118 } 119 return 0; 120 } 121
