src/dissect/dissect.c

   1 /***
   2   This file is part of systemd.
   3
   4   Copyright 2016 Lennart Poettering
   5
   6   systemd is free software; you can redistribute it and/or modify it
   7   under the terms of the GNU Lesser General Public License as published by
   8   the Free Software Foundation; either version 2.1 of the License, or
   9   (at your option) any later version.
  10
  11   systemd is distributed in the hope that it will be useful, but
  12   WITHOUT ANY WARRANTY; without even the implied warranty of
  13   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  14   Lesser General Public License for more details.
  15
  16   You should have received a copy of the GNU Lesser General Public License
  17   along with systemd; If not, see <http://www.gnu.org/licenses/>.
  18 ***/
  19
  20 #include <fcntl.h>
  21 #include <stdio.h>
  22 #include <getopt.h>
  23
  24 #include "architecture.h"
  25 #include "dissect-image.h"
  26 #include "hexdecoct.h"
  27 #include "log.h"
  28 #include "loop-util.h"
  29 #include "string-util.h"
  30 #include "util.h"
  31
  32 static enum {
  33         ACTION_DISSECT,
  34         ACTION_MOUNT,
  35 } arg_action = ACTION_DISSECT;
  36 static const char *arg_image = NULL;
  37 static const char *arg_path = NULL;
  38 static DissectImageFlags arg_flags = DISSECT_IMAGE_REQUIRE_ROOT|DISSECT_IMAGE_DISCARD_ON_LOOP;
  39 static void *arg_root_hash = NULL;
  40 static size_t arg_root_hash_size = 0;
  41
  42 static void help(void) {
  43         printf("%s [OPTIONS...] IMAGE\n"
  44                "%s [OPTIONS...] --mount IMAGE PATH\n"
  45                "Dissect a file system OS image.\n\n"
  46                "  -h --help            Show this help\n"
  47                "     --version         Show package version\n"
  48                "  -m --mount           Mount the image to the specified directory\n"
  49                "  -r --read-only       Mount read-only\n"
  50                "     --discard=MODE    Choose 'discard' mode (disabled, loop, all, crypto)\n"
  51                "     --root-hash=HASH  Specify root hash for verity\n",
  52                program_invocation_short_name,
  53                program_invocation_short_name);
  54 }
  55
  56 static int parse_argv(int argc, char *argv[]) {
  57
  58         enum {
  59                 ARG_VERSION = 0x100,
  60                 ARG_DISCARD,
  61                 ARG_ROOT_HASH,
  62         };
  63
  64         static const struct option options[] = {
  65                 { "help",      no_argument,       NULL, 'h'           },
  66                 { "version",   no_argument,       NULL, ARG_VERSION   },
  67                 { "mount",     no_argument,       NULL, 'm'           },
  68                 { "read-only", no_argument,       NULL, 'r'           },
  69                 { "discard",   required_argument, NULL, ARG_DISCARD   },
  70                 { "root-hash", required_argument, NULL, ARG_ROOT_HASH },
  71                 {}
  72         };
  73
  74         int c, r;
  75
  76         assert(argc >= 0);
  77         assert(argv);
  78
  79         while ((c = getopt_long(argc, argv, "hmr", options, NULL)) >= 0) {
  80
  81                 switch (c) {
  82
  83                 case 'h':
  84                         help();
  85                         return 0;
  86
  87                 case ARG_VERSION:
  88                         return version();
  89
  90                 case 'm':
  91                         arg_action = ACTION_MOUNT;
  92                         break;
  93
  94                 case 'r':
  95                         arg_flags |= DISSECT_IMAGE_READ_ONLY;
  96                         break;
  97
  98                 case ARG_DISCARD: {
  99                         DissectImageFlags flags;
 100
 101                         if (streq(optarg, "disabled"))
 102                                 flags = 0;
 103                         else if (streq(optarg, "loop"))
 104                                 flags = DISSECT_IMAGE_DISCARD_ON_LOOP;
 105                         else if (streq(optarg, "all"))
 106                                 flags = DISSECT_IMAGE_DISCARD_ON_LOOP | DISSECT_IMAGE_DISCARD;
 107                         else if (streq(optarg, "crypt"))
 108                                 flags = DISSECT_IMAGE_DISCARD_ANY;
 109                         else {
 110                                 log_error("Unknown --discard= parameter: %s", optarg);
 111                                 return -EINVAL;
 112                         }
 113                         arg_flags = (arg_flags & ~DISSECT_IMAGE_DISCARD_ANY) | flags;
 114
 115                         break;
 116                 }
 117
 118                 case ARG_ROOT_HASH: {
 119                         void *p;
 120                         size_t l;
 121
 122                         r = unhexmem(optarg, strlen(optarg), &p, &l);
 123                         if (r < 0)
 124                                 return log_error_errno(r, "Failed to parse root hash: %s", optarg);
 125                         if (l < sizeof(sd_id128_t)) {
 126                                 log_error("Root hash must be at least 128bit long: %s", optarg);
 127                                 free(p);
 128                                 return -EINVAL;
 129                         }
 130
 131                         free(arg_root_hash);
 132                         arg_root_hash = p;
 133                         arg_root_hash_size = l;
 134                         break;
 135                 }
 136
 137                 case '?':
 138                         return -EINVAL;
 139
 140                 default:
 141                         assert_not_reached("Unhandled option");
 142                 }
 143
 144         }
 145
 146         switch (arg_action) {
 147
 148         case ACTION_DISSECT:
 149                 if (optind + 1 != argc) {
 150                         log_error("Expected a file path as only argument.");
 151                         return -EINVAL;
 152                 }
 153
 154                 arg_image = argv[optind];
 155                 arg_flags |= DISSECT_IMAGE_READ_ONLY;
 156                 break;
 157
 158         case ACTION_MOUNT:
 159                 if (optind + 2 != argc) {
 160                         log_error("Expected a file path and mount point path as only arguments.");
 161                         return -EINVAL;
 162                 }
 163
 164                 arg_image = argv[optind];
 165                 arg_path = argv[optind + 1];
 166                 break;
 167
 168         default:
 169                 assert_not_reached("Unknown action.");
 170         }
 171
 172         return 1;
 173 }
 174
 175 int main(int argc, char *argv[]) {
 176         _cleanup_(loop_device_unrefp) LoopDevice *d = NULL;
 177         _cleanup_(decrypted_image_unrefp) DecryptedImage *di = NULL;
 178         _cleanup_(dissected_image_unrefp) DissectedImage *m = NULL;
 179         int r;
 180
 181         log_parse_environment();
 182         log_open();
 183
 184         r = parse_argv(argc, argv);
 185         if (r <= 0)
 186                 goto finish;
 187
 188         r = loop_device_make_by_path(arg_image, (arg_flags & DISSECT_IMAGE_READ_ONLY) ? O_RDONLY : O_RDWR, &d);
 189         if (r < 0) {
 190                 log_error_errno(r, "Failed to set up loopback device: %m");
 191                 goto finish;
 192         }
 193
 194         if (!arg_root_hash) {
 195                 r = root_hash_load(arg_image, &arg_root_hash, &arg_root_hash_size);
 196                 if (r < 0) {
 197                         log_error_errno(r, "Failed to read root hash file for %s: %m", arg_image);
 198                         goto finish;
 199                 }
 200         }
 201
 202         r = dissect_image(d->fd, arg_root_hash, arg_root_hash_size, arg_flags, &m);
 203         if (r == -ENOPKG) {
 204                 log_error_errno(r, "Couldn't identify a suitable partition table or file system in %s.", arg_image);
 205                 goto finish;
 206         }
 207         if (r == -EADDRNOTAVAIL) {
 208                 log_error_errno(r, "No root partition for specified root hash found in %s.", arg_image);
 209                 goto finish;
 210         }
 211         if (r == -ENOTUNIQ) {
 212                 log_error_errno(r, "Multiple suitable root partitions found in image %s.", arg_image);
 213                 goto finish;
 214         }
 215         if (r == -ENXIO) {
 216                 log_error_errno(r, "No suitable root partition found in image %s.", arg_image);
 217                 goto finish;
 218         }
 219         if (r == -EPROTONOSUPPORT) {
 220                 log_error_errno(r, "Device %s is loopback block device with partition scanning turned off, please turn it on.", arg_image);
 221                 goto finish;
 222         }
 223         if (r < 0) {
 224                 log_error_errno(r, "Failed to dissect image: %m");
 225                 goto finish;
 226         }
 227
 228         switch (arg_action) {
 229
 230         case ACTION_DISSECT: {
 231                 unsigned i;
 232
 233                 for (i = 0; i < _PARTITION_DESIGNATOR_MAX; i++) {
 234                         DissectedPartition *p = m->partitions + i;
 235                         int k;
 236
 237                         if (!p->found)
 238                                 continue;
 239
 240                         printf("Found %s '%s' partition",
 241                                p->rw ? "writable" : "read-only",
 242                                partition_designator_to_string(i));
 243
 244                         if (!sd_id128_is_null(p->uuid))
 245                                 printf(" (UUID " SD_ID128_FORMAT_STR ")", SD_ID128_FORMAT_VAL(p->uuid));
 246
 247                         if (p->fstype)
 248                                 printf(" of type %s", p->fstype);
 249
 250                         if (p->architecture != _ARCHITECTURE_INVALID)
 251                                 printf(" for %s", architecture_to_string(p->architecture));
 252
 253                         k = PARTITION_VERITY_OF(i);
 254                         if (k >= 0)
 255                                 printf(" %s verity", m->partitions[k].found ? "with" : "without");
 256
 257                         if (p->partno >= 0)
 258                                 printf(" on partition #%i", p->partno);
 259
 260                         if (p->node)
 261                                 printf(" (%s)", p->node);
 262
 263                         putchar('\n');
 264                 }
 265
 266                 break;
 267         }
 268
 269         case ACTION_MOUNT:
 270                 r = dissected_image_decrypt_interactively(m, NULL, arg_root_hash, arg_root_hash_size, arg_flags, &di);
 271                 if (r < 0)
 272                         goto finish;
 273
 274                 r = dissected_image_mount(m, arg_path, arg_flags);
 275                 if (r < 0) {
 276                         log_error_errno(r, "Failed to mount image: %m");
 277                         goto finish;
 278                 }
 279
 280                 if (di) {
 281                         r = decrypted_image_relinquish(di);
 282                         if (r < 0) {
 283                                 log_error_errno(r, "Failed to relinquish DM devices: %m");
 284                                 goto finish;
 285                         }
 286                 }
 287
 288                 loop_device_relinquish(d);
 289                 break;
 290
 291         default:
 292                 assert_not_reached("Unknown action.");
 293         }
 294
 295 finish:
 296         free(arg_root_hash);
 297         return r < 0 ? EXIT_FAILURE : EXIT_SUCCESS;
 298 }