e2fsprogs/tune2fs.c

   1 /* vi: set sw=4 ts=4: */
   2 /*
   3  * tune2fs: utility to modify EXT2 filesystem
   4  *
   5  * Busybox'ed (2009) by Vladimir Dronnikov <dronnikov@gmail.com>
   6  *
   7  * Licensed under GPLv2, see file LICENSE in this source tree.
   8  */
   9 //config:config TUNE2FS
  10 //config:       bool "tune2fs"
  11 //config:       default n  # off: it is too limited compared to upstream version
  12 //config:       help
  13 //config:         tune2fs allows the system administrator to adjust various tunable
  14 //config:         filesystem parameters on Linux ext2/ext3 filesystems.
  15
  16 //applet:IF_TUNE2FS(APPLET(tune2fs, BB_DIR_SBIN, BB_SUID_DROP))
  17
  18 //TODO alias to "tune2fs -L LABEL": //applet:IF_E2LABEL(APPLET_ODDNAME(e2label, tune2fs, BB_DIR_SBIN, BB_SUID_DROP, e2label))
  19
  20 //kbuild:lib-$(CONFIG_TUNE2FS) += tune2fs.o
  21
  22 //usage:#define tune2fs_trivial_usage
  23 //usage:       "[-c MAX_MOUNT_COUNT] "
  24 ////usage:     "[-e errors-behavior] [-g group] "
  25 //usage:       "[-i DAYS] "
  26 ////usage:     "[-j] [-J journal-options] [-l] [-s sparse-flag] "
  27 ////usage:     "[-m reserved-blocks-percent] [-o [^]mount-options[,...]] "
  28 ////usage:     "[-r reserved-blocks-count] [-u user] "
  29 //usage:       "[-C MOUNT_COUNT] "
  30 //usage:       "[-L LABEL] "
  31 ////usage:     "[-M last-mounted-dir] [-O [^]feature[,...]] "
  32 ////usage:     "[-T last-check-time] [-U UUID] "
  33 //usage:       "BLOCKDEV"
  34 //usage:
  35 //usage:#define tune2fs_full_usage "\n\n"
  36 //usage:       "Adjust filesystem options on ext[23] filesystems"
  37
  38 #include "libbb.h"
  39 #include <linux/fs.h>
  40 #include "bb_e2fs_defs.h"
  41
  42 // storage helpers
  43 char BUG_wrong_field_size(void);
  44 #define STORE_LE(field, value) \
  45 do { \
  46         if (sizeof(field) == 4) \
  47                 field = SWAP_LE32(value); \
  48         else if (sizeof(field) == 2) \
  49                 field = SWAP_LE16(value); \
  50         else if (sizeof(field) == 1) \
  51                 field = (value); \
  52         else \
  53                 BUG_wrong_field_size(); \
  54 } while (0)
  55
  56 #define FETCH_LE32(field) \
  57         (sizeof(field) == 4 ? SWAP_LE32(field) : BUG_wrong_field_size())
  58
  59 enum {
  60         OPT_L = 1 << 0, // label
  61         OPT_c = 1 << 1, // max mount count
  62         OPT_i = 1 << 2, // check interval
  63         OPT_C = 1 << 3, // current mount count
  64 };
  65
  66 int tune2fs_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
  67 int tune2fs_main(int argc UNUSED_PARAM, char **argv)
  68 {
  69         unsigned opts;
  70         const char *label, *str_c, *str_i, *str_C;
  71         struct ext2_super_block *sb;
  72         int fd;
  73
  74         opt_complementary = "=1";
  75         opts = getopt32(argv, "L:c:i:C:", &label, &str_c, &str_i, &str_C);
  76         if (!opts)
  77                 bb_show_usage();
  78         argv += optind; // argv[0] -- device
  79
  80         // read superblock
  81         fd = xopen(argv[0], O_RDWR);
  82         xlseek(fd, 1024, SEEK_SET);
  83         sb = xzalloc(1024);
  84         xread(fd, sb, 1024);
  85
  86         // mangle superblock
  87         //STORE_LE(sb->s_wtime, time(NULL)); - why bother?
  88
  89         if (opts & OPT_C) {
  90                 int n = xatoi_range(str_C, 1, 0xfffe);
  91                 STORE_LE(sb->s_mnt_count, (unsigned)n);
  92         }
  93
  94         // set the label
  95         if (opts & OPT_L)
  96                 safe_strncpy((char *)sb->s_volume_name, label, sizeof(sb->s_volume_name));
  97
  98         if (opts & OPT_c) {
  99                 int n = xatoi_range(str_c, -1, 0xfffe);
 100                 if (n == 0)
 101                         n = -1;
 102                 STORE_LE(sb->s_max_mnt_count, (unsigned)n);
 103         }
 104
 105         if (opts & OPT_i) {
 106                 unsigned n = xatou_range(str_i, 0, (unsigned)0xffffffff / (24*60*60)) * 24*60*60;
 107                 STORE_LE(sb->s_checkinterval, n);
 108         }
 109
 110         // write superblock
 111         xlseek(fd, 1024, SEEK_SET);
 112         xwrite(fd, sb, 1024);
 113
 114         if (ENABLE_FEATURE_CLEAN_UP) {
 115                 free(sb);
 116         }
 117
 118         xclose(fd);
 119         return EXIT_SUCCESS;
 120 }