src/dissect/dissect.c

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