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 "string-util.h"
  13 #include "strv.h"
  14 #include "user-util.h"
  15 #include "util.h"
  16
  17 static enum {
  18         ACTION_DISSECT,
  19         ACTION_MOUNT,
  20 } arg_action = ACTION_DISSECT;
  21 static const char *arg_image = NULL;
  22 static const char *arg_path = NULL;
  23 static DissectImageFlags arg_flags = DISSECT_IMAGE_REQUIRE_ROOT|DISSECT_IMAGE_DISCARD_ON_LOOP;
  24 static void *arg_root_hash = NULL;
  25 static size_t arg_root_hash_size = 0;
  26
  27 static void help(void) {
  28         printf("%s [OPTIONS...] IMAGE\n"
  29                "%s [OPTIONS...] --mount IMAGE PATH\n"
  30                "Dissect a file system OS image.\n\n"
  31                "  -h --help            Show this help\n"
  32                "     --version         Show package version\n"
  33                "  -m --mount           Mount the image to the specified directory\n"
  34                "  -r --read-only       Mount read-only\n"
  35                "     --discard=MODE    Choose 'discard' mode (disabled, loop, all, crypto)\n"
  36                "     --root-hash=HASH  Specify root hash for verity\n",
  37                program_invocation_short_name,
  38                program_invocation_short_name);
  39 }
  40
  41 static int parse_argv(int argc, char *argv[]) {
  42
  43         enum {
  44                 ARG_VERSION = 0x100,
  45                 ARG_DISCARD,
  46                 ARG_ROOT_HASH,
  47         };
  48
  49         static const struct option options[] = {
  50                 { "help",      no_argument,       NULL, 'h'           },
  51                 { "version",   no_argument,       NULL, ARG_VERSION   },
  52                 { "mount",     no_argument,       NULL, 'm'           },
  53                 { "read-only", no_argument,       NULL, 'r'           },
  54                 { "discard",   required_argument, NULL, ARG_DISCARD   },
  55                 { "root-hash", required_argument, NULL, ARG_ROOT_HASH },
  56                 {}
  57         };
  58
  59         int c, r;
  60
  61         assert(argc >= 0);
  62         assert(argv);
  63
  64         while ((c = getopt_long(argc, argv, "hmr", options, NULL)) >= 0) {
  65
  66                 switch (c) {
  67
  68                 case 'h':
  69                         help();
  70                         return 0;
  71
  72                 case ARG_VERSION:
  73                         return version();
  74
  75                 case 'm':
  76                         arg_action = ACTION_MOUNT;
  77                         break;
  78
  79                 case 'r':
  80                         arg_flags |= DISSECT_IMAGE_READ_ONLY;
  81                         break;
  82
  83                 case ARG_DISCARD: {
  84                         DissectImageFlags flags;
  85
  86                         if (streq(optarg, "disabled"))
  87                                 flags = 0;
  88                         else if (streq(optarg, "loop"))
  89                                 flags = DISSECT_IMAGE_DISCARD_ON_LOOP;
  90                         else if (streq(optarg, "all"))
  91                                 flags = DISSECT_IMAGE_DISCARD_ON_LOOP | DISSECT_IMAGE_DISCARD;
  92                         else if (streq(optarg, "crypt"))
  93                                 flags = DISSECT_IMAGE_DISCARD_ANY;
  94                         else {
  95                                 log_error("Unknown --discard= parameter: %s", optarg);
  96                                 return -EINVAL;
  97                         }
  98                         arg_flags = (arg_flags & ~DISSECT_IMAGE_DISCARD_ANY) | flags;
  99
 100                         break;
 101                 }
 102
 103                 case ARG_ROOT_HASH: {
 104                         void *p;
 105                         size_t l;
 106
 107                         r = unhexmem(optarg, strlen(optarg), &p, &l);
 108                         if (r < 0)
 109                                 return log_error_errno(r, "Failed to parse root hash '%s': %m", optarg);
 110                         if (l < sizeof(sd_id128_t)) {
 111                                 log_error("Root hash must be at least 128bit long: %s", optarg);
 112                                 free(p);
 113                                 return -EINVAL;
 114                         }
 115
 116                         free(arg_root_hash);
 117                         arg_root_hash = p;
 118                         arg_root_hash_size = l;
 119                         break;
 120                 }
 121
 122                 case '?':
 123                         return -EINVAL;
 124
 125                 default:
 126                         assert_not_reached("Unhandled option");
 127                 }
 128
 129         }
 130
 131         switch (arg_action) {
 132
 133         case ACTION_DISSECT:
 134                 if (optind + 1 != argc) {
 135                         log_error("Expected a file path as only argument.");
 136                         return -EINVAL;
 137                 }
 138
 139                 arg_image = argv[optind];
 140                 arg_flags |= DISSECT_IMAGE_READ_ONLY;
 141                 break;
 142
 143         case ACTION_MOUNT:
 144                 if (optind + 2 != argc) {
 145                         log_error("Expected a file path and mount point path as only arguments.");
 146                         return -EINVAL;
 147                 }
 148
 149                 arg_image = argv[optind];
 150                 arg_path = argv[optind + 1];
 151                 break;
 152
 153         default:
 154                 assert_not_reached("Unknown action.");
 155         }
 156
 157         return 1;
 158 }
 159
 160 int main(int argc, char *argv[]) {
 161         _cleanup_(loop_device_unrefp) LoopDevice *d = NULL;
 162         _cleanup_(decrypted_image_unrefp) DecryptedImage *di = NULL;
 163         _cleanup_(dissected_image_unrefp) DissectedImage *m = NULL;
 164         int r;
 165
 166         log_parse_environment();
 167         log_open();
 168
 169         r = parse_argv(argc, argv);
 170         if (r <= 0)
 171                 goto finish;
 172
 173         r = loop_device_make_by_path(arg_image, (arg_flags & DISSECT_IMAGE_READ_ONLY) ? O_RDONLY : O_RDWR, &d);
 174         if (r < 0) {
 175                 log_error_errno(r, "Failed to set up loopback device: %m");
 176                 goto finish;
 177         }
 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                         log_error_errno(r, "Failed to read root hash file for %s: %m", arg_image);
 183                         goto finish;
 184                 }
 185         }
 186
 187         r = dissect_image_and_warn(d->fd, arg_image, arg_root_hash, arg_root_hash_size, arg_flags, &m);
 188         if (r < 0)
 189                 goto finish;
 190
 191         switch (arg_action) {
 192
 193         case ACTION_DISSECT: {
 194                 unsigned i;
 195
 196                 for (i = 0; i < _PARTITION_DESIGNATOR_MAX; i++) {
 197                         DissectedPartition *p = m->partitions + i;
 198                         int k;
 199
 200                         if (!p->found)
 201                                 continue;
 202
 203                         printf("Found %s '%s' partition",
 204                                p->rw ? "writable" : "read-only",
 205                                partition_designator_to_string(i));
 206
 207                         if (!sd_id128_is_null(p->uuid))
 208                                 printf(" (UUID " SD_ID128_FORMAT_STR ")", SD_ID128_FORMAT_VAL(p->uuid));
 209
 210                         if (p->fstype)
 211                                 printf(" of type %s", p->fstype);
 212
 213                         if (p->architecture != _ARCHITECTURE_INVALID)
 214                                 printf(" for %s", architecture_to_string(p->architecture));
 215
 216                         k = PARTITION_VERITY_OF(i);
 217                         if (k >= 0)
 218                                 printf(" %s verity", m->partitions[k].found ? "with" : "without");
 219
 220                         if (p->partno >= 0)
 221                                 printf(" on partition #%i", p->partno);
 222
 223                         if (p->node)
 224                                 printf(" (%s)", p->node);
 225
 226                         putchar('\n');
 227                 }
 228
 229                 r = dissected_image_acquire_metadata(m);
 230                 if (r < 0) {
 231                         log_error_errno(r, "Failed to acquire image metadata: %m");
 232                         goto finish;
 233                 }
 234
 235                 if (m->hostname)
 236                         printf("  Hostname: %s\n", m->hostname);
 237
 238                 if (!sd_id128_is_null(m->machine_id))
 239                         printf("Machine ID: " SD_ID128_FORMAT_STR "\n", SD_ID128_FORMAT_VAL(m->machine_id));
 240
 241                 if (!strv_isempty(m->machine_info)) {
 242                         char **p, **q;
 243
 244                         STRV_FOREACH_PAIR(p, q, m->machine_info)
 245                                 printf("%s %s=%s\n",
 246                                        p == m->machine_info ? "Mach. Info:" : "           ",
 247                                        *p, *q);
 248                 }
 249
 250                 if (!strv_isempty(m->os_release)) {
 251                         char **p, **q;
 252
 253                         STRV_FOREACH_PAIR(p, q, m->os_release)
 254                                 printf("%s %s=%s\n",
 255                                        p == m->os_release ? "OS Release:" : "           ",
 256                                        *p, *q);
 257                 }
 258
 259                 break;
 260         }
 261
 262         case ACTION_MOUNT:
 263                 r = dissected_image_decrypt_interactively(m, NULL, arg_root_hash, arg_root_hash_size, arg_flags, &di);
 264                 if (r < 0)
 265                         goto finish;
 266
 267                 r = dissected_image_mount(m, arg_path, UID_INVALID, arg_flags);
 268                 if (r < 0) {
 269                         log_error_errno(r, "Failed to mount image: %m");
 270                         goto finish;
 271                 }
 272
 273                 if (di) {
 274                         r = decrypted_image_relinquish(di);
 275                         if (r < 0) {
 276                                 log_error_errno(r, "Failed to relinquish DM devices: %m");
 277                                 goto finish;
 278                         }
 279                 }
 280
 281                 loop_device_relinquish(d);
 282                 break;
 283
 284         default:
 285                 assert_not_reached("Unknown action.");
 286         }
 287
 288 finish:
 289         free(arg_root_hash);
 290         return r < 0 ? EXIT_FAILURE : EXIT_SUCCESS;
 291 }