src/dissect/dissect.c

   1 /* SPDX-License-Identifier: LGPL-2.1+ */
   2
   3 #include <fcntl.h>
   4 #include <getopt.h>
   5 #include <linux/loop.h>
   6 #include <stdio.h>
   7
   8 #include "architecture.h"
   9 #include "dissect-image.h"
  10 #include "hexdecoct.h"
  11 #include "log.h"
  12 #include "loop-util.h"
  13 #include "main-func.h"
  14 #include "string-util.h"
  15 #include "strv.h"
  16 #include "user-util.h"
  17 #include "util.h"
  18
  19 static enum {
  20         ACTION_DISSECT,
  21         ACTION_MOUNT,
  22 } arg_action = ACTION_DISSECT;
  23 static const char *arg_image = NULL;
  24 static const char *arg_path = NULL;
  25 static DissectImageFlags arg_flags = DISSECT_IMAGE_REQUIRE_ROOT|DISSECT_IMAGE_DISCARD_ON_LOOP;
  26 static void *arg_root_hash = NULL;
  27 static size_t arg_root_hash_size = 0;
  28
  29 STATIC_DESTRUCTOR_REGISTER(arg_root_hash, freep);
  30
  31 static void help(void) {
  32         printf("%s [OPTIONS...] IMAGE\n"
  33                "%s [OPTIONS...] --mount IMAGE PATH\n"
  34                "Dissect a file system OS image.\n\n"
  35                "  -h --help            Show this help\n"
  36                "     --version         Show package version\n"
  37                "  -m --mount           Mount the image to the specified directory\n"
  38                "  -r --read-only       Mount read-only\n"
  39                "     --discard=MODE    Choose 'discard' mode (disabled, loop, all, crypto)\n"
  40                "     --root-hash=HASH  Specify root hash for verity\n",
  41                program_invocation_short_name,
  42                program_invocation_short_name);
  43 }
  44
  45 static int parse_argv(int argc, char *argv[]) {
  46
  47         enum {
  48                 ARG_VERSION = 0x100,
  49                 ARG_DISCARD,
  50                 ARG_ROOT_HASH,
  51         };
  52
  53         static const struct option options[] = {
  54                 { "help",      no_argument,       NULL, 'h'           },
  55                 { "version",   no_argument,       NULL, ARG_VERSION   },
  56                 { "mount",     no_argument,       NULL, 'm'           },
  57                 { "read-only", no_argument,       NULL, 'r'           },
  58                 { "discard",   required_argument, NULL, ARG_DISCARD   },
  59                 { "root-hash", required_argument, NULL, ARG_ROOT_HASH },
  60                 {}
  61         };
  62
  63         int c, r;
  64
  65         assert(argc >= 0);
  66         assert(argv);
  67
  68         while ((c = getopt_long(argc, argv, "hmr", options, NULL)) >= 0) {
  69
  70                 switch (c) {
  71
  72                 case 'h':
  73                         help();
  74                         return 0;
  75
  76                 case ARG_VERSION:
  77                         return version();
  78
  79                 case 'm':
  80                         arg_action = ACTION_MOUNT;
  81                         break;
  82
  83                 case 'r':
  84                         arg_flags |= DISSECT_IMAGE_READ_ONLY;
  85                         break;
  86
  87                 case ARG_DISCARD: {
  88                         DissectImageFlags flags;
  89
  90                         if (streq(optarg, "disabled"))
  91                                 flags = 0;
  92                         else if (streq(optarg, "loop"))
  93                                 flags = DISSECT_IMAGE_DISCARD_ON_LOOP;
  94                         else if (streq(optarg, "all"))
  95                                 flags = DISSECT_IMAGE_DISCARD_ON_LOOP | DISSECT_IMAGE_DISCARD;
  96                         else if (streq(optarg, "crypt"))
  97                                 flags = DISSECT_IMAGE_DISCARD_ANY;
  98                         else
  99                                 return log_error_errno(SYNTHETIC_ERRNO(EINVAL),
 100                                                        "Unknown --discard= parameter: %s",
 101                                                        optarg);
 102                         arg_flags = (arg_flags & ~DISSECT_IMAGE_DISCARD_ANY) | flags;
 103
 104                         break;
 105                 }
 106
 107                 case ARG_ROOT_HASH: {
 108                         void *p;
 109                         size_t l;
 110
 111                         r = unhexmem(optarg, strlen(optarg), &p, &l);
 112                         if (r < 0)
 113                                 return log_error_errno(r, "Failed to parse root hash '%s': %m", optarg);
 114                         if (l < sizeof(sd_id128_t)) {
 115                                 log_error("Root hash must be at least 128bit long: %s", optarg);
 116                                 free(p);
 117                                 return -EINVAL;
 118                         }
 119
 120                         free(arg_root_hash);
 121                         arg_root_hash = p;
 122                         arg_root_hash_size = l;
 123                         break;
 124                 }
 125
 126                 case '?':
 127                         return -EINVAL;
 128
 129                 default:
 130                         assert_not_reached("Unhandled option");
 131                 }
 132
 133         }
 134
 135         switch (arg_action) {
 136
 137         case ACTION_DISSECT:
 138                 if (optind + 1 != argc)
 139                         return log_error_errno(SYNTHETIC_ERRNO(EINVAL),
 140                                                "Expected a file path as only argument.");
 141
 142                 arg_image = argv[optind];
 143                 arg_flags |= DISSECT_IMAGE_READ_ONLY;
 144                 break;
 145
 146         case ACTION_MOUNT:
 147                 if (optind + 2 != argc)
 148                         return log_error_errno(SYNTHETIC_ERRNO(EINVAL),
 149                                                "Expected a file path and mount point path as only arguments.");
 150
 151                 arg_image = argv[optind];
 152                 arg_path = argv[optind + 1];
 153                 break;
 154
 155         default:
 156                 assert_not_reached("Unknown action.");
 157         }
 158
 159         return 1;
 160 }
 161
 162 static int run(int argc, char *argv[]) {
 163         _cleanup_(loop_device_unrefp) LoopDevice *d = NULL;
 164         _cleanup_(decrypted_image_unrefp) DecryptedImage *di = NULL;
 165         _cleanup_(dissected_image_unrefp) DissectedImage *m = NULL;
 166         int r;
 167
 168         log_parse_environment();
 169         log_open();
 170
 171         r = parse_argv(argc, argv);
 172         if (r <= 0)
 173                 return r;
 174
 175         r = loop_device_make_by_path(arg_image, (arg_flags & DISSECT_IMAGE_READ_ONLY) ? O_RDONLY : O_RDWR, LO_FLAGS_PARTSCAN, &d);
 176         if (r < 0)
 177                 return log_error_errno(r, "Failed to set up loopback device: %m");
 178
 179         if (!arg_root_hash) {
 180                 r = root_hash_load(arg_image, &arg_root_hash, &arg_root_hash_size);
 181                 if (r < 0)
 182                         return log_error_errno(r, "Failed to read root hash file for %s: %m", arg_image);
 183         }
 184
 185         r = dissect_image_and_warn(d->fd, arg_image, arg_root_hash, arg_root_hash_size, arg_flags, &m);
 186         if (r < 0)
 187                 return r;
 188
 189         switch (arg_action) {
 190
 191         case ACTION_DISSECT: {
 192                 unsigned i;
 193
 194                 for (i = 0; i < _PARTITION_DESIGNATOR_MAX; i++) {
 195                         DissectedPartition *p = m->partitions + i;
 196                         int k;
 197
 198                         if (!p->found)
 199                                 continue;
 200
 201                         printf("Found %s '%s' partition",
 202                                p->rw ? "writable" : "read-only",
 203                                partition_designator_to_string(i));
 204
 205                         if (!sd_id128_is_null(p->uuid))
 206                                 printf(" (UUID " SD_ID128_FORMAT_STR ")", SD_ID128_FORMAT_VAL(p->uuid));
 207
 208                         if (p->fstype)
 209                                 printf(" of type %s", p->fstype);
 210
 211                         if (p->architecture != _ARCHITECTURE_INVALID)
 212                                 printf(" for %s", architecture_to_string(p->architecture));
 213
 214                         k = PARTITION_VERITY_OF(i);
 215                         if (k >= 0)
 216                                 printf(" %s verity", m->partitions[k].found ? "with" : "without");
 217
 218                         if (p->partno >= 0)
 219                                 printf(" on partition #%i", p->partno);
 220
 221                         if (p->node)
 222                                 printf(" (%s)", p->node);
 223
 224                         putchar('\n');
 225                 }
 226
 227                 r = dissected_image_acquire_metadata(m);
 228                 if (r < 0)
 229                         return log_error_errno(r, "Failed to acquire image metadata: %m");
 230
 231                 if (m->hostname)
 232                         printf("  Hostname: %s\n", m->hostname);
 233
 234                 if (!sd_id128_is_null(m->machine_id))
 235                         printf("Machine ID: " SD_ID128_FORMAT_STR "\n", SD_ID128_FORMAT_VAL(m->machine_id));
 236
 237                 if (!strv_isempty(m->machine_info)) {
 238                         char **p, **q;
 239
 240                         STRV_FOREACH_PAIR(p, q, m->machine_info)
 241                                 printf("%s %s=%s\n",
 242                                        p == m->machine_info ? "Mach. Info:" : "           ",
 243                                        *p, *q);
 244                 }
 245
 246                 if (!strv_isempty(m->os_release)) {
 247                         char **p, **q;
 248
 249                         STRV_FOREACH_PAIR(p, q, m->os_release)
 250                                 printf("%s %s=%s\n",
 251                                        p == m->os_release ? "OS Release:" : "           ",
 252                                        *p, *q);
 253                 }
 254
 255                 break;
 256         }
 257
 258         case ACTION_MOUNT:
 259                 r = dissected_image_decrypt_interactively(m, NULL, arg_root_hash, arg_root_hash_size, arg_flags, &di);
 260                 if (r < 0)
 261                         return r;
 262
 263                 r = dissected_image_mount(m, arg_path, UID_INVALID, arg_flags);
 264                 if (r < 0)
 265                         return log_error_errno(r, "Failed to mount image: %m");
 266
 267                 if (di) {
 268                         r = decrypted_image_relinquish(di);
 269                         if (r < 0)
 270                                 return log_error_errno(r, "Failed to relinquish DM devices: %m");
 271                 }
 272
 273                 loop_device_relinquish(d);
 274                 break;
 275
 276         default:
 277                 assert_not_reached("Unknown action.");
 278         }
 279
 280         return 0;
 281 }
 282
 283 DEFINE_MAIN_FUNCTION(run);