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 #ifdef HAVE_LIBUUID
  55 static int change_info(const char *devname, const char *label, const char *uuid)
  56 #else
  57 static int change_info(const char *devname, const char *label,
  58                        const char *uuid __attribute__((__unused__)))
  59 #endif
  60 {
  61         int fd;
  62
  63         fd = open(devname, O_RDWR);
  64         if (fd < 0) {
  65                 warn(_("cannot open %s"), devname);
  66                 goto err;
  67         }
  68 #ifdef HAVE_LIBUUID
  69         /* Write the uuid if it was provided */
  70         if (uuid) {
  71                 uuid_t newuuid;
  72
  73                 if (uuid_parse(uuid, newuuid) == -1)
  74                         warnx(_("failed to parse UUID: %s"), uuid);
  75                 else {
  76                         if (lseek(fd, SWAP_UUID_OFFSET, SEEK_SET) !=
  77                                                         SWAP_UUID_OFFSET) {
  78                                 warn(_("%s: failed to seek to swap UUID"), devname);
  79                                 goto err;
  80
  81                         } else if (write_all(fd, newuuid, sizeof(newuuid))) {
  82                                 warn(_("%s: failed to write UUID"), devname);
  83                                 goto err;
  84                         }
  85                 }
  86         }
  87 #endif
  88         /* Write the label if it was provided */
  89         if (label) {
  90                 char newlabel[SWAP_LABEL_LENGTH];
  91
  92                 if (lseek(fd, SWAP_LABEL_OFFSET, SEEK_SET) != SWAP_LABEL_OFFSET) {
  93                         warn(_("%s: failed to seek to swap label "), devname);
  94                         goto err;
  95                 }
  96                 memset(newlabel, 0, sizeof(newlabel));
  97                 xstrncpy(newlabel, label, sizeof(newlabel));
  98
  99                 if (strlen(label) > strlen(newlabel))
 100                         warnx(_("label is too long. Truncating it to '%s'"),
 101                                         newlabel);
 102                 if (write_all(fd, newlabel, sizeof(newlabel))) {
 103                         warn(_("%s: failed to write label"), devname);
 104                         goto err;
 105                 }
 106         }
 107
 108         if (close_fd(fd) != 0) {
 109                 warn(_("write failed: %s"), devname);
 110                 return -1;
 111         }
 112         return 0;
 113 err:
 114         if (fd >= 0)
 115                 close(fd);
 116         return -1;
 117 }
 118
 119 static void __attribute__((__noreturn__)) usage(void)
 120 {
 121         FILE *out = stdout;
 122         fputs(USAGE_HEADER, out);
 123         fprintf(out, _(" %s [options] <device>\n"),
 124                 program_invocation_short_name);
 125
 126         fputs(USAGE_SEPARATOR, out);
 127         fputs(_("Display or change the label or UUID of a swap area.\n"), out);
 128
 129         fputs(USAGE_OPTIONS, out);
 130         fputs(_(" -L, --label <label> specify a new label\n"
 131                 " -U, --uuid <uuid>   specify a new uuid\n"), out);
 132         fputs(USAGE_SEPARATOR, out);
 133         printf(USAGE_HELP_OPTIONS(21));
 134         printf(USAGE_MAN_TAIL("swaplabel(8)"));
 135         exit(EXIT_SUCCESS);
 136 }
 137
 138 int main(int argc, char *argv[])
 139 {
 140         blkid_probe pr = NULL;
 141         char *uuid = NULL, *label = NULL, *devname;
 142         int c, rc = -1;
 143
 144         static const struct option longopts[] = {
 145             { "help",      no_argument,       NULL, 'h' },
 146             { "version",   no_argument,       NULL, 'V' },
 147             { "label",     required_argument, NULL, 'L' },
 148             { "uuid",      required_argument, NULL, 'U' },
 149             { NULL,        0, NULL, 0 }
 150         };
 151
 152         setlocale(LC_ALL, "");
 153         bindtextdomain(PACKAGE, LOCALEDIR);
 154         textdomain(PACKAGE);
 155         close_stdout_atexit();
 156
 157         while ((c = getopt_long(argc, argv, "hVL:U:", longopts, NULL)) != -1) {
 158                 switch (c) {
 159                 case 'h':
 160                         usage();
 161                         break;
 162                 case 'V':
 163                         print_version(EXIT_SUCCESS);
 164                 case 'L':
 165                         label = optarg;
 166                         break;
 167                 case 'U':
 168 #ifdef HAVE_LIBUUID
 169                         uuid = optarg;
 170 #else
 171                         warnx(_("ignore -U (UUIDs are unsupported)"));
 172 #endif
 173                         break;
 174                 default:
 175                         errtryhelp(EXIT_FAILURE);
 176                 }
 177         }
 178
 179         if (optind == argc) {
 180                 warnx(_("no device specified"));
 181                 errtryhelp(EXIT_FAILURE);
 182         }
 183         devname = argv[optind];
 184         pr = get_swap_prober(devname);
 185         if (pr) {
 186                 if (uuid || label)
 187                         rc = change_info(devname, label, uuid);
 188                 else
 189                         rc  = print_info(pr);
 190                 blkid_free_probe(pr);
 191         }
 192         return rc ? EXIT_FAILURE : EXIT_SUCCESS;
 193 }
 194