disk-utils/swaplabel.c

   1 /*
   2  * swaplabel.c - Print or change the label / UUID of a swap partition
   3  *
   4  * Copyright (C) 2010 Jason Borden <jborden@bluehost.com>
   5  * Copyright (C) 2010 Karel Zak <kzak@redhat.com>
   6  *
   7  * Usage: swaplabel [-L label] [-U UUID] device
   8  *
   9  * This file may be redistributed under the terms of the GNU Public License
  10  * version 2 or later.
  11  *
  12  */
  13 #include <stdio.h>
  14 #include <stddef.h>
  15 #include <string.h>
  16 #include <fcntl.h>
  17 #include <sys/types.h>
  18 #include <sys/stat.h>
  19 #include <unistd.h>
  20 #include <stdlib.h>
  21 #include <getopt.h>
  22
  23 #ifdef HAVE_LIBUUID
  24 # include <uuid.h>
  25 #endif
  26
  27 #include "c.h"
  28 #include "nls.h"
  29 #include "all-io.h"
  30 #include "strutils.h"
  31 #include "closestream.h"
  32
  33 #include "swapheader.h"
  34 #include "swapprober.h"
  35
  36 #define SWAP_UUID_OFFSET        (offsetof(struct swap_header_v1_2, uuid))
  37 #define SWAP_LABEL_OFFSET       (offsetof(struct swap_header_v1_2, volume_name))
  38
  39 /* Print the swap partition information */
  40 static int print_info(blkid_probe pr)
  41 {
  42         const char *data;
  43
  44         if (!blkid_probe_lookup_value(pr, "LABEL", &data, NULL))
  45                 printf("LABEL: %s\n", data);
  46
  47         if (!blkid_probe_lookup_value(pr, "UUID", &data, NULL))
  48                 printf("UUID:  %s\n", data);
  49
  50         return 0;
  51 }
  52
  53 /* Change the swap partition info */
  54 static int change_info(const char *devname, const char *label, const char *uuid)
  55 {
  56         int fd;
  57
  58         fd = open(devname, O_RDWR);
  59         if (fd < 0) {
  60                 warn(_("cannot open %s"), devname);
  61                 goto err;
  62         }
  63 #ifdef HAVE_LIBUUID
  64         /* Write the uuid if it was provided */
  65         if (uuid) {
  66                 uuid_t newuuid;
  67
  68                 if (uuid_parse(uuid, newuuid) == -1)
  69                         warnx(_("failed to parse UUID: %s"), uuid);
  70                 else {
  71                         if (lseek(fd, SWAP_UUID_OFFSET, SEEK_SET) !=
  72                                                         SWAP_UUID_OFFSET) {
  73                                 warn(_("%s: failed to seek to swap UUID"), devname);
  74                                 goto err;
  75
  76                         } else if (write_all(fd, newuuid, sizeof(newuuid))) {
  77                                 warn(_("%s: failed to write UUID"), devname);
  78                                 goto err;
  79                         }
  80                 }
  81         }
  82 #endif
  83         /* Write the label if it was provided */
  84         if (label) {
  85                 char newlabel[SWAP_LABEL_LENGTH];
  86
  87                 if (lseek(fd, SWAP_LABEL_OFFSET, SEEK_SET) != SWAP_LABEL_OFFSET) {
  88                         warn(_("%s: failed to seek to swap label "), devname);
  89                         goto err;
  90                 }
  91                 memset(newlabel, 0, sizeof(newlabel));
  92                 xstrncpy(newlabel, label, sizeof(newlabel));
  93
  94                 if (strlen(label) > strlen(newlabel))
  95                         warnx(_("label is too long. Truncating it to '%s'"),
  96                                         newlabel);
  97                 if (write_all(fd, newlabel, sizeof(newlabel))) {
  98                         warn(_("%s: failed to write label"), devname);
  99                         goto err;
 100                 }
 101         }
 102
 103         if (close_fd(fd) != 0) {
 104                 warn(_("write failed: %s"), devname);
 105                 return -1;
 106         }
 107         return 0;
 108 err:
 109         if (fd >= 0)
 110                 close(fd);
 111         return -1;
 112 }
 113
 114 static void __attribute__((__noreturn__)) usage(void)
 115 {
 116         FILE *out = stdout;
 117         fputs(USAGE_HEADER, out);
 118         fprintf(out, _(" %s [options] <device>\n"),
 119                 program_invocation_short_name);
 120
 121         fputs(USAGE_SEPARATOR, out);
 122         fputs(_("Display or change the label or UUID of a swap area.\n"), out);
 123
 124         fputs(USAGE_OPTIONS, out);
 125         fputs(_(" -L, --label <label> specify a new label\n"
 126                 " -U, --uuid <uuid>   specify a new uuid\n"), out);
 127         fputs(USAGE_SEPARATOR, out);
 128         printf(USAGE_HELP_OPTIONS(21));
 129         printf(USAGE_MAN_TAIL("swaplabel(8)"));
 130         exit(EXIT_SUCCESS);
 131 }
 132
 133 int main(int argc, char *argv[])
 134 {
 135         blkid_probe pr = NULL;
 136         char *uuid = NULL, *label = NULL, *devname;
 137         int c, rc = -1;
 138
 139         static const struct option longopts[] = {
 140             { "help",      no_argument,       NULL, 'h' },
 141             { "version",   no_argument,       NULL, 'V' },
 142             { "label",     required_argument, NULL, 'L' },
 143             { "uuid",      required_argument, NULL, 'U' },
 144             { NULL,        0, NULL, 0 }
 145         };
 146
 147         setlocale(LC_ALL, "");
 148         bindtextdomain(PACKAGE, LOCALEDIR);
 149         textdomain(PACKAGE);
 150         atexit(close_stdout);
 151
 152         while ((c = getopt_long(argc, argv, "hVL:U:", longopts, NULL)) != -1) {
 153                 switch (c) {
 154                 case 'h':
 155                         usage();
 156                         break;
 157                 case 'V':
 158                         printf(UTIL_LINUX_VERSION);
 159                         return EXIT_SUCCESS;
 160                 case 'L':
 161                         label = optarg;
 162                         break;
 163                 case 'U':
 164 #ifdef HAVE_LIBUUID
 165                         uuid = optarg;
 166 #else
 167                         warnx(_("ignore -U (UUIDs are unsupported)"));
 168 #endif
 169                         break;
 170                 default:
 171                         errtryhelp(EXIT_FAILURE);
 172                 }
 173         }
 174
 175         if (optind == argc) {
 176                 warnx(_("no device specified"));
 177                 errtryhelp(EXIT_FAILURE);
 178         }
 179         devname = argv[optind];
 180         pr = get_swap_prober(devname);
 181         if (pr) {
 182                 if (uuid || label)
 183                         rc = change_info(devname, label, uuid);
 184                 else
 185                         rc  = print_info(pr);
 186                 blkid_free_probe(pr);
 187         }
 188         return rc ? EXIT_FAILURE : EXIT_SUCCESS;
 189 }
 190